>S1 


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THE  EMBRYOLOGY,  DEVELOPMENT,  AND  ANATOMY 

OF  THE 

NOSE,  PARANASAL  SINUSES,  NASOLACRIMAL  PASSAGEWAYS, 
AND  OLFACTORY  ORGAN  IN  MAN 


SCHAEFFER 


Photographs  of  cast  of  nasal  fossae  and  paranasal  (accessory)  sinuses  viewed  from  both  the  right 
(above)  and  cranial  (below)  aspects.  From  an  adult  male.  Natural  size. 

/,  frontal  sinuses;  m.  maxillary  sinuses;  s,  sphenoidal  sinuses;  e,  ethmoidal  cells;  I,  nasolacrimal  duct; 
nc.  nasal  cavity;  c,  right  choana  (posterior  nan's) ;  np,  nasopharynx;  im.  interior  nasal  meatus. 


THE  NOSE,  PARANASAL  SINUSES, 
NASOLACRIMAL   PASSAGE- 
WAYS, AND  OLFACTORY 
ORGAN  IN  MAN 


A  GENETIC,  DEVELOPMENTAL,  AND 

ANATOM1CO-PHYSIOLOGICAL 

CONSIDERATION 


BY 


J.  PARSONS  SCHAEFFER,  A.M.,  M.D.,  Ph.D. 

PROFESSOR     OF     ANATOMY  'AND    DIRECTOR     OF    THE    DANIEL    BAUGH    INSTITUTE    O'F    ANATOMY  OF  THE  JEFFERSON 

MEDICAL     COLLEGE     OF     PHILADELPHIA;     FORMERLY     ASSISTANT  rPROFESSOR    OF    ANATOMY,    CORNELL, 

UNIVERSITY  MEDICAL  COLLEGE  AND  PROFESSOR  OF  ANATOMY,  YALE  UNIVERSITY  MEDICAL  SCHOOL 


WITH  204  ILLUSTRATIONS  OF  WHICH  18  ARE 
PRINTED  IN  COLOR 


PHILADELPHIA 
P.   BLAKISTON'S  SON  &  CO. 

1012   WALNUT   STREET 


COPYRIGHT,  1920,  BY  P.  BLAKISTON'S  SON  &  Co. 


Biooedial 


WV 

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PREFACE 

The  object  of  this  monograph  is  to  present  a  study  of  the  embryology, 
development  and  anatomy,  both  microscopic  and  macroscopic,  of  the 
human  nose,  the  paranasal  sinuses,  the  olfactory  organ  and  certain  other 
ancillary  structures.  The  study  had  its  inception  in  work  done  on  the 
maxillary  sinus  in  1907  at  Cornell  University.  The  field  of  investigation 
was  gradually  extended  so  as  to  include  ultimately  the  entire  nasal  region 
and  its  immediate  environs.  The  study  was  continued  at  intervals  at 
Cornell  University  (1907-11),  at  Yale  University  (1911-14),  and  at  the 
Jefferson  Medical  College  since  1914. 

A  number  of  papers  on  various  phases  of  the  study  were  published 
from  time  to  time  as  the  work  progressed,  and  the  author  now  takes  the 
liberty  of  drawing  upon  them  in  this  connection;  this  being  alike  true  for 
text,  diagrams,  tables  and  illustrations.  Most  of  the  matter,  however, 
appears  in  new  form  and  for  the  first  time. 

All  work  must  needs  be  based  in  part  on  the  labors  of  the  past  and 
the  author  is  not  unmindful  of  the  help  derived  from  the  recorded  observa- 
tions of  other  workers  in  the  field.  No  attempt,  however,  is  here  made  to 
review  the  literature  on  the  subject:  had  this  been  done,  the  size  of  the 
book  would  have  been  increased  far  beyond  the  limits  set  for  it.  The  aim 
has  been  to  present  a  more  or  less  comprehensive  account  of  personal 
studies  and  observations  on  the  genesis,  development,  and  anatomy  of 
the  nose  and  its  related  parts  rather  than  to  compile  a  fairly  voluminous 
literature  with  its  not  infrequent  diverse  conclusions.  In  large  measure, 
therefore,  the  descriptions  and  discussions  as  set  forth  in  subsequent 
chapters  and  paragraphs  are  based  upon  researches  by  the  author,  extend- 
ing over  a  period  of  years.  Likewise  most  of  the  illustrations  are  based 
upon  preparations,  reconstructions,  and  dissections  by  the  author  and 
reproduced  either  by  him  or  under  his  directions.  Of  course,  where  vital 
points  are  at  issue  or  where  the  author  feels  that  his  own  observations  are 
inadequate,  due  reference  is  made  of  the  work  and  conclusions  of  other 
investigators.  Moreover,  a  certain  number  of  illustrations  are  after  other 
writers  for  which  proper  credit  is  given  in  the  respective  legends. 

vii 


viii  PREFACE 

Seldom,  indeed,  is  it  that  all  phases  of  a  study  reach  a  state  of  finality. 
Unfortunately,  this  is  true  in  the  present  connection,  for  in  some  instances 
it  has  become  necessary  to  assume  certain  conclusions  tentatively  from 
established  and  related  facts  and  the  clinical  evidence  at  hand.  This, 
however,  seems  warranted,  for  unless  we  exercise  some  scientific  judgment 
and  imagination  no  progress  can  be  made.  Further  study  and  analyses 
may  affirm  or  deny  the  assumptions.  It  is  no  easy  task,  for  example, 
to  establish  with  certainty  all  the  fiber  tracts  in  some  neuron  circuits. 
Moreover,  when  a  few  hours  markedly  alter  a  structure  during  its  develop- 
mental stages,  it  is  obviously  difficult  to  have  at  hand  and  in  serial  sections 
human  embryos  closely  enough  graded  to  demonstrate  every  possible 
point  that  arises  in  a  study  such  as  this.  Fortunately,  experience  has 
shown  that  mammalian  embryos  are  of  great  value  in  filling  in  our  gaps 
of  knowledge  of  human  embryology  and  until  human  embryos  of  the 
proper  ages  fall  into  the  hands  of  competent  observers,  it  is  altogether 
proper  to  assume  certain  hypotheses  based  upon  the  study  of  other  and 
related  forms. 

In  order  to  consider  all  portions  of  the  nose  and  the  cognate  regions 
and  structures  and  bring  the  results  of  the  observations  and  studies  within 
the  limits  of  an  average-sized  volume,  it  was  necessary  in  many  instances 
to  omit  the  records  of  many  detailed  observations  and  to  record  the  essen- 
tials only.  This  is  more  or  less  true  throughout  the  work,  but  especially 
so  in  connection  with  the  central  olfactory  organ  and  the  individual  bones 
that  comprise  the  nasal  framework.  Important  and  essential  points  are,  of 
course,  treated  in  greater  detail.  Moreover,  where  brevity  of  description 
and  discussion  would  have  befogged  clearness  some  otherwise  unessential 
details  are  recorded.  It  is,  of  course,  obvious  that  any  one  of  the  chapters 
and,  indeed,  in  some  cases  parts  of  chapters  could  be  profitably  amplified 
into  individual  monographs.  The  purpose  and  plan  of  the  book,  however, 
did  not  require  such  amplification. 

Despite  the  large  amount  of  materials  studied  over  a  period  of 
years,  the  author  recognizes  that  this  work  is  incomplete,  but  hopes  the 
descriptions,  discussions  and  suggestions  will  be  found  helpful  by  physi- 
cians and  surgeons  and  undergraduates  in  medicine. 

The  author  is  not  unmindful  of  the  many  opportunities  afforded  for 
the  furtherance  of  this  work  at  the  Cornell  University  Medical  College, 
the  Yale  University  Medical  School,  and  the  Jefferson  Medical  College. 
Nor  of  his  indebtedness  to  the  Mutter  Museum  of  the  College  of  Physi- 
cians of  Philadelphia  for  the  privilege  of  studying  certain  materials,  and 
to  its  curator,  Dr.  Clarence  Hoffman,  for  many  courtesies.  Moreover, 


PREFACE  ix 

thanks  are  due  Dr.  H.  E.  Radasch  for  the  preparation  of  tissues  from  the 
author's  collection  for  Figs.  181  and  182,  Miss  Bremerman  for  valued  help 
in  the  preparation  of  the  manuscript  and  proof-reading,  and  Miss  Neely 
and  Mrs.  Schaeffer  for  certain  translations. 

The  index  is  the  work  of  Dr.  Benjamin  Lipshutz. 

The  author  wishes  to  express  his  obligations  to  the  publishers  for 
their  hearty  cooperation  and  generosity. 

J.  PARSONS  SCHAEFFER. 

4634  SPRUCE  STREET, 
PHILADELPHIA,  PENNA. 


CONTENTS 

INTRODUCTION xix 

CHAPTER  I 

GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 3 

The  Proton  and  Rudiment 3 

The  Nasal  Pits 3 

Frontonasal  Process 4 

Nasal  Processes 4 

Maxillary  Process 4 

The  Primitive  (Primary)  Nasal  Fossae 7 

General  Statement 7 

The  Bucconasal  Membranes 9 

The  Primitive  Choanae 9 

The  Nares ' 10 

The  Primitive  Palate u 

The  Definitive  Palate 12 

The  Definitive  Choanae 14 

The  Primary  Nasal  Septum 16 

The  Secondary  Nasal  Septum    .    .    . 16 

The  Definitive  (Secondary)  Nasal  Fossae 17 

General  Statement 17 

The  Lateral  Nasal  Wall 18 

General  Statement 18 

The  Major  Nasal  Conchae  and  Meatuses 18 

General  Statement 18 

The  Inferior  Nasal  Concha 20 

The  Inferior  and  Middle  Nasal  Meatuses 20 

The  Ethmoidal  Conchae  and  Meatuses 21 

The  Nasoturbinal  (agger  nasi) 26 

The  Nasal  Atrium 26 

The  Olfactory  Sulcus 26 

The  Sphenoethmoidal  Recess 26 

Nomenclature 27 

The  Minor  Nasal  Conchae  and  Meatuses 27 

General  Statement 27 

The  Descending  Ramus  of  the  Meatus  Nasi  Medius 28 

General  Statement 28 

The  Suprabullar  Furrow  or  Recess 30 

The  Bullar  Furrow 31 

The  Infrabullar  Furrow 31 

The  Infundibulum  Ethmoidale 31 

The  Superior  Bullar  Fold  or  Concha 32 

The  Inferior  Bullar  Fold  or  Concha .-    •    •  32 

The  Infundibular  Fold  or  Concha 33 

The  Processus  Uncinatus 33 

xi 


xii  CONTENTS 

The  Ascending  Ramus  of  the  Meatus  Nasi  Medius 33 

Recessus  Frontalis 33 

The  Frontal  Folds  or  Conchae 33 

The  Frontal  Furrows  or  Pits 33 

The  Descending  Ramus  of  the  Meatus  Nasi  Superior 35 

The  Rudiments  of  the  Paranasal  Sinuses 36 

The  Maxillary 36 

The  Ethmoidal 36 

The  Frontal 36 

The  Sphenoidal 36 

The  Definitive  Nasal  Septum 37 

The  Development  of  the  Nasal  Skeleton 38 

The  Cartilaginous  Nasal  Capsule 38 

^Ossification  of  Elements 40 

The  Ethmoid  Bone 40 

The  Vomer 41 

The  Maxilloturbinal 42 

The  Palate  Bone 42 

The  Nasal  Bone 42 

The  Lacrimal  Bone 42 

The  Sphenoid  Bone 43 

The  Sphenoturbinal 43 

The  Maxilla 44 

The  Frontal  Bone 45 

Skeleton  Changes  Incident  to  Growth 45 

The  Epithelium  of  the  Primitive  Nasal  Fossae 47 

The  Olfactory  Nerves 47 

The  Nasal  Glands 47 

The  Vomeronasal  Organ 47 

The  Embryonic  External  Nose 48 

The  Nasolacrimal  Passageways 49 

Congenital  Defects  of  the  Nose .Si 


CHAPTER  II 

THE  DEFINITIVE  NOSE 61 

General  Statement 61 

The  External  Nose 61 

General  Statement 61 

The  Bones  of  the  External  Nose 63 

The  Cartilages  of  the  External  Nose 66 

The  Greater  Alar  Cartilage 68 

The  Lateral  Nasal  Cartilage 69 

The  Lesser  Alar  Cartilages 70 

The  Sesamoid  Nasal  Cartilages 70 

The  Muscles  of  the  External  Nose 70 

The  Internal  Nose 7I 

General  Statement ....  71 

The  Nares 72 

The  Vestibule 73 


CONTENTS  xiii 

The  Choanae  (Posterior  Nares) 73 

The  Floor  of  the  Nasal  Cavity 75 

The  Roof  of  the  Nasal  Fossa 77 

The  Median  Wall  of  the  Nasal  Fossa 77 

General  Statement 77 

The  Osseous  Portion  of  the  Nasal  Septum 78 

The  Vomer 79 

The  Mesethmoid 80 

Other  Osseous  Elements 81 

The  Cartilaginous  Portion  of  the  Nasal  Septum 81 

The  Cartilage  of  the  Septum 81 

The  Vomeronasal  Cartilages 82 

The  Greater  Alar  Cartilage 82 

The  Membranous  Portion  of  the  Nasal  Septum 82 

Asymmetry  of  the  Nasal  Septum 83 

Perforation  of  the  Nasal  Septum 86 

X  The  Lateral  Wall  of  the  Nasal  Fossa 86 

General  Statement 86 

The  Osseous  Framework 87 

The  Inferior  Nasal  Concha 88 

The  Inferior  Nasal  Meatus 89 

The  Ostium  of  the  Nasolacrimal  Duct 89 

The  Middle  Nasal  Concha 90 

The  Middle  Nasal  Meatus 91 

The  Ethmoidal  Infundibulum 92 

The  Uncinate  Process 93 

The  Ethmoidal  Bulla 94 

The  Suprabullar  Furrow  or  Recess 95 

The  Frontal  Recess 95 

The  Superior  Nasal  Concha 95 

The  Superior  Nasal  Meatus 95 

The  First  Supreme  Nasal  Concha 96 

The  First  Supreme  Nasal  Meatus 96 

The  Sphenoethmoidal  Recess 96 

The  Second  and  Third  Supreme  Nasal  Conchae 97 

The  Agger  Nasi 97 

The  Nasal  Atrium 97 

The  Olfactory  Sulcus 97 

CHAPTER  III 

THE  MAXILLARY  SINUS 101 

The  Fetal  Stage 101 

The  Childhood  Stage 104 

The  Adult  Stage 109 

General  Considerations 109 

The  Relations  of  the  Sinus  Floor  to  the  Nasal  Floor in 

The  Relations  of  the  Maxillary  Sinus  to  the  Teeth 112 

Ridges,  Crescentic  Projections  and  Septa 116 

Duplication  of  the  Maxillary  Sinus 113 

The  Size  of  the  Maxillary  Sinus .122 


xiv  CONTENTS 

The  Maxillary  Ostium    .  .    .   127 

Duplication  of  the  Maxillary  Ostium 129 

The  Accessory  Maxillary  Ostium  .13° 

Concluding  Considerations     .    .  133 

CHAPTER  IV 

THE  FRONTAL  SINUS   .  .    .  139 

The  Fetal  Stage   .    .  .    .  139 

The  Childhood  Stage  143 

The  Adult  Stage  ...  ....  146 

General  Considerations 146 

Size  of  the  Adult  Frontal  Sinus 147 

Extensive  Pneumatizations 147 

Supernumerary  Frontal  Sinuses 1 50 

The  Frontal  Bulla 152 

Frontal  Sinus  Diverticula 154 

Agenesis  of  the  Frontal  Sinus 157 

The  Nasof rental  Connections 160 

The  Nasofrontal  Duct 166 

Concluding  Considerations 168 

CHAPTER  V 

THE  SPHENOIDAL  SINUS 175 

The  Fetal  Stage 175 

The  Childhood  Stage 176 

The  Adult  Stage 178 

General  Considerations 178 

The  Topography  of  the  Adult  Sphenoidal  Sinus 180 

Osseous  Septa  and  Recesses  of  the  Sphenoidal  Sinus 183 

Diverticula  of  the  Sphenoidal  Sinus 184 

The  Sphenoidal  Septum 187 

The  Sphenoidal  Ostium 187 

The  Size  of  the  Sphenoidal  Sinus 188 

The  Hypophysis  Cerebri  as  Related  to  the  Sphenoidal  Sinus      188 

The  Optic  Nerve  and  Commissure  as  Related  to  the  Paranasal  Sinuses 190 

The  Cavernous  Sinus  and  Contained  Structures  as  Related  to  the  Sphenoidal 

Sinus 193 

Diminutive  Sphenoidal  Sinuses 197 

Agenesis  of  Sphenoidal  Sinuses     198 

Concluding  Considerations 199 

CHAPTER  VI 

THE  ETHMOIDAL  CELLS 205 

The  Fetal  Stage 20=; 

The  Childhood  Stage 206 

The  Adult  Stage 211 

General  Considerations 211 

Classification    .  212 


CONTENTS  xv 

Dehiscences 212 

Size  of  the  Ethmoidal  Labyrinth : 214 

The  Anterior  Ethmoidal  Cells 215 

The  Frontal  Group 216 

The  Infundibular  Group -216 

The  Bullar  Group 218 

The  Frontal  Bulla 218 

The  Posterior  Ethmoidal  Cells 219 

The  Conchal  Cells 221 

The  Middle  Conchal  Sinus 226 

Concluding  Considerations 226 

CHAPTER  VII 

THE  NASOLACRIMAL  PASSAGEWAYS 237 

General  Statement 237 

Genetic  and  Developmental  Anatomy 237 

Variations  and  Anomalies 242 

The  Lacrimal  Fossa  and  the  Nasolacrimal  Canal 244 

The  Lacrimal  Ducts 247 

The  Lacrimal  Sac 248 

The  Nasolacrimal  Duct 248 

The  Nasolacrimal-duct  Diverticula  and  Valves 250 

The  Nasal  and  Paranasal  Relations  of  the  Membranous  Nasolacrimal  Passageways  .  252 

The  Nasolacrimal  Ostium 253 

Concluding  Remarks 255 

CHAPTER  VIII 

THE  NASAL  Mucous  MEMBRANE     261 

General  Statement 261 

The  Nasal  Vestibule 261 

The  Nasal  Fossa 261 

The  Respiratory  Portion 262 

The  Olfactory  Portion 266 

The  Paranasal  Sinuses 268 

The  Vomeronasal  Organ 270 

The  Genital  Spots  (so-called) 271 

CHAPTER  IX 

THE  BLOOD-  AND  LYMPH-VASCULAR  SYSTEMS  OF  THE  NOSE  AND  THE  PARANASAL  SINUSES  275 

The  Arterial  Supply 275 

The  Sphenopalatine  Artery 275 

The  Anterior  and  Posterior  Ethmoidal  Arteries 277 

The  Descending  Palatine  Artery 278 

The  Pharyngeal  Artery 278 

The  Infraorbital  Artery 278 

The  External  Maxillary  (Facial)  Artery 278 

The  Venous  Supply 278 


xvi  CONTENTS 

The  Lymphatic  Supply 279 

The  Nasal  Cavity    .    .    .    .• 280 

The  Paranasal  Sinuses 281 

The  External  Nose 282 

CHAPTER  X 

THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES  OF  THE  NOSE  AND  PARANASAL 

SINUSES 285 

The  Nerves  of  Common  Sensation 285 

General  Statement 285 

The  Ophthalmic  Nerve 285 

The  Maxillary  Nerve 285 

The  Central  Connections 285 

The  Sympathetic  Nerves 286 

General  Statement 286 

Sympathetic  Efferent  Neurons 288 

Sympathetic  Afferent  Neurons 289 

The  Vasoconstrictor  Center 290 

The  Vasodilator  Center 290 

Reflex  Circuits 291 

Reflex  Nasal  Manifestations 293 

Naso-sexual  Relations 296 

The  Transference  and  Reference  of  Afferent  Impulses 302 

The  Peripheral  Nerves  and  the  Sphenopalatine  Ganglion 306 

The  Maxillary  Division  of  the  Trigeminal  Nerve  in  its  Nasal  Distribution ....  306 
The  Ophthalmic  Division  of  the  Trigeminal  Nerve  in  its  Nasal  Distribution  .    .    .313 

The  Sphenopalatine  Ganglion 314 

General  Statement 314 

The  Motor  Root 314 

The  Sympathetic  Root 316 

The  Sensory  Root 317 

The  Anatomic  Relations  of  the  Sphenopalatine  Ganglion 318 

The  Anatomic  Relations  of  the  Nerve  of  the  Pterygoid  Canal  (Vidian  Nerve)    .  320 

CHAPTER  XI 

THE  OLFACTORY  APPARATUS  PROPER 325 

General  Statement 325 

The  Peripheral  Organ 325 

The  Olfactory  Nerve 326 

The  Terminal  Nerve 326 

The  Vomeronasal  Nerve 327 

The  Central  Organ 328 

The  Olfactory  Brain 328 

General  Statement 328 

The  Olfactory  Bulb 330 

The  Olfactory  Tract 330 

The  Olfactory  Trigone 331 

The  Anterior  Perforated  Substance 331 


CONTENTS  xvii 

The  Parolfactory  Area 331 

The  Subcallosal  Gyrus 333 

The  Supracallosal  Gyrus 333 

The  Fascia  Dentata  Hippocampi 333 

The  Hippocampus 334 

The  Uncus 334 

The  Fornix 335 

The  Septum  Pellucidum 335 

The  Habenular  Trigone 336 

The  Medullary  Stria  of  the  Thalamus.    . 336 

The  Mammillary  Bodies 337 

The  Terminal  Stria  of  the  Thalamus 338 

The  Amygdaloid  Nucleus 338 

The  Olfactory  Reflex  and  Cortical  Connections 338 

The  Olfactory  Pathways 341 

The  Relations  of  the  Brain  to  the  Walls  of  the  Nasal  Fossae  and  the  Paranasal 
Sinuses 344 

CHAPTER  XII 


347 

347 

350 

354 

ERRATUM 

360 

xix,  10th  line  from  bottom,  for  "anatomy"  read  "embryology." 


xv  i  CONTENTS 

The  Lymphatic  Supply 279 

The  Nasal  Cavity    .    .    .    .• 280 

The  Paranasal  Sinuses 281 

The  External  Nose 282 

CHAPTER  X 

THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES  or  THE  NOSE  AND  PARANASAL 

SINUSES 285 

The  Nerves  of  Common  Sensation 285 

General  Statement 285 

The  Ophthalmic  Nerve 285 

The  Maxillary  Nerve 285 

The  Central  Connections 285 

The  Sympathetic  Nerves 286 

General  Statement 286 

Sympathetic  Efferent  Neurons 288 

Sympathetic  Afferent  Neurons 289 

The  Vasoconstrictor  Center 290 

The  Vasodilator  Center 290 

Reflex  Circuits     .    . 

Reflex  Nasal  Manifes 

Naso-sexual  Relation 

The  Transference  am 

The  Peripheral  Nerv< 

The  Maxillary  Div 

The  Ophthalmic  D 

The  Sphenopalatin 

General  Stateme 

The  Motor  Root 314 

The  Sympathetic  Root 316 

The  Sensory  Root 317 

The  Anatomic  Relations  of  the  Sphenopalatine  Ganglion 318 

The  Anatomic  Relations  of  the  Nerve  of  the  Pterygoid  Canal  (Vidian  Nerve)    .  320 

CHAPTER  XI 

THE  OLFACTORY  APPARATUS  PROPER 325 

General  Statement 325 

The  Peripheral  Organ 325 

The  Olfactory  Nerve 326 

The  Terminal  Nerve 326 

The  Vomeronasal  Nerve 327 

The  Central  Organ 328 

The  Olfactory  Brain 328 

General  Statement 328 

The  Olfactory  Bulb 33o 

The  Olfactory  Tract 330 

The  Olfactory  Trigone 331 

The  Anterior  Perforated  Substance 331 


CONTENTS  xvii 

The  Parolfactory  Area 331 

The  Subcallosal  Gyrus 333 

The  Supracallosal  Gyrus 333 

The  Fascia  Dentata  Hippocampi 333 

The  Hippocampus - 334 

The  Uncus 334 

The  Fornix 335 

The  Septum  Pellucidum 335 

The  Habenular  Trigone 336 

The  Medullary  Stria  of  the  Thalamus.    .    . 336 

The  Mammillary  Bodies 337 

The  Terminal  Stria  of  the  Thalamus 338 

The  Amygdaloid  Nucleus 338 

The  Olfactory  Reflex  and  Cortical  Connections 338 

The  Olfactory  Pathways 341 

The  Relations  of  the  Brain  to  the  Walls  of  the  Nasal  Fossae  and  the  Paranasal 
Sinuses 344 

CHAPTER  XII 

PHYSIOLOGICAL  ADDENDA 347 

The  Nose  Proper 347 

The  Paranasal  Sinuses 350 

Olfactory  Sensation 354 

INDEX 360 


INTRODUCTION 

Much  productive  ground  remains  unworked  in  human  anatomy  and 
ancillary  subjects,  despite  the  unfortunate  belief  of  many  graduates  in 
medicine  that  the  study  of  anatomy  has  reached  a  state  of  finality  and 
that  the  anatomical  field  has  been  fully  gleaned  of  its  harvest.  When  one 
recalls,  however,  that  modern  anatomical  teaching  and  research  no  longer 
recognize  the  unfortunate  historic  distinction  between  macroscopic  (gross) 
and  microscopic  (minute)  anatomy;  that  the  human  body  is  now  con- 
sidered from  the  phyletic,  the  ontogenetic,  the  physiologic,  the  histologic 
and  the  gross  viewpoints ;  that  modern  anatomy  is  concerned  with  evolu- 
tion, heredity  and  variation,  it  is  clearly  obvious  that  anatomy  is  no  longer 
restricted  to  a  purely  descriptive  study,  but  that  its  domain  has  expanded 
into  its  proper  spheres  and  that  many  problems  await  solution.  Even 
descriptive  or  gross  anatomy  is  not  without  its  problems,  many  of  vital 
and  practical  importance. 

Tt  is  very  difficult  and  unsatisfactory  to  approach  an  anatomical 
problem  without  a  basic  conception  of  the  underlying  genetic  and  develop- 
mental history.  In  order  to  properly  interpret  points  in  the  adult  anatomy 
of  a  region,  it  not  infrequently  is  necessary  to  revert  to  the  embryology 
of  the  part  or  region  concerned.  Many  faulty  statements  extant  in  the 
literature  are  doubtless  the  result  of  drawing  conclusions  from  a  study  of 
too  few  specimens,  of  studying  adult  material  alone,  and  of  errors  in  in- 
terpretation due  to  the  fact  that  embryologic  and  adult  studies  were  not 
carried  on  simultaneously.  A  prominent  surgeon  recently  recommended 
a  study  and  basic  understanding  of  embryology  "as  one  of  the  founda- 
tion stones  of  surgical  training."  Be  that  as  it  may,  it  certainly  cannot 
be  gainsaid  that  a  knowledge  of  human  anatomy  is  of  paramount  impor- 
tance in  a  comprehensive  understanding  and  interpretation  of  both  macro- 
scopic and  microscopic  anatomy,  both  for  the  medical  student  and  the 
physician  and  surgeon  in  the  practical  field. 

Variations  in  the  anatomy  of  the  human  body  are  not  uncommon, 
both  ontogenetic  and  phylogenetic.  In  the  former  one  has  to  contend  with 
the  very  important  group  of  human  variants  generally  spoken  of  as  errors 
in  development —  congenital  defects.  There  are  also  progressive  and 
reversional  variants  encountered.  The  phyletic  variations  have  to  do 
with  the  hereditary  reappearance  of  ancestral  characters.  When  one 


xx  INTRODUCTION 

recalls  that  "each  organism  in  the  course  of  its  individual  ontogeny 
repeats  the  history  of  its  ancestral  development"  the  appearance  of  remote 
characters  in  man  is  more  comprehensible.  In  order,  therefore,  to  deal 
intelligently  with  variations,  one  needs,  indeed,  not  infrequently  to  hark 
back  not  only  to  the  developmental  history  of  the  individual,  but  to  the 
ancestral  history  of  man  as  well. 

Entirely  apart  from  the  variations  referred  to  above  there  are  the 
ever-recurring  variations  in  what  may  be  termed  the  gross  anatomic  type 
of  a  structure,  organ,  or  region  of  the  human  body.  These  too,  strictly 
speaking,  are  ontogenetic  variations  in  that  they  result  from  the  differen- 
tiation of  the  individual  embryo  and  lead  to  the  development  of  a  certain 
anatomic  type  of  the  adult  body.  Some  of  these  variations  or  types  occur 
so  infrequently  and  are  so  unlike  all  others  that  one  must  assume  that 
they  result  from  atypical  differentiation  of  the  embryo,  leading  to  an 
anomalous  or  abnormal  structure,  organ,  or  region  in  the  adult.  On  the 
other  hand,  certain  variations  in  the  anatomy  of  many  parts  of  the  human 
body  occur  with  sufficient  frequence  to  justify  the  establishment  of  normal 
anatomic  types.  This,  of  course,  opposes  the  conception  of  an  unvarying 
typical  or  ideal  anatomic  type  and  all  departures  therefrom  as  anomalies. 

In  a  general  sense  only  do  a  large  series  of  human  bodies  conform  in 
their  detailed  gross  anatomy  to  a  so-called  typical  form.  It  would  appear 
from  some  recent  studies  that  not  a  few  of  our  traditional  ideas  found  in 
some  clinical  text-books  in  explanation  of  certain  physical  signs  and  other 
conditions  encountered  in  the  human  body  from  time  to  time  are  at 
variance  with  anatomic  facts.  Conclusions  drawn  hastily  and  not  suf- 
ficiently verified  by  extensive  anatomic  studies  are  not  of  infrequent 
occurrence.  The  idea  of  an  unvarying  typical  form  in  the  gross  anatomy 
of  the  human  body  appears  more  or  less  prevalent  in  the  practical  field. 
There  is,  of  course,  great  need  of  extensive  study  of  the  various  regions, 
organs,  and  other  structures  of  the  body;  the  conclusions  to  be  based 
upon  a  large  number  of  cadavers.  This  has  been  done  for  some  regions 
and  splendid  monographs  and  records  are  extant  on  such  researches. 
The  work,  however,  must  be  extended  and  ulitmately  be  made  to  include 
all  of  the  important  regions  of  the  body.  Such  studies,  if  based  on  a 
arg  e  amount  of  material  and  discriminating  work,  will  establish  anatomic 
types.  What  is  desired  is  not  the  average  nor  the  mean  but  the  various 
gross  anatomic  types  of  a  region,  organ  or  structure,  wherever  and  when- 
ever it  is  possible  to  establish  such  with  a  fair  degree  of  certainty.  After 
the  normal  anatomic  types  are  established,  the  anomalies  of  the  human 
body  will  naturally  find  their  proper  place,  as  will  also  the  average  and  the 


INTRODUCTION  xxi 

mean.  This  work  should  be  made  to  include  the  several  ages  of  the 
childhood  period,  the  pubertal  stage,  and  that  of  the  adult.  It  is  obvious 
that  such  exhaustive  anatomical  considerations  of  special  regions  and 
organs  are  not  the  province  of  the  general  text-books  of  human  anatomy, 
but  clearly  the  function  of  anatomic  monographs. 

In  studying  a  given  region  of  the  body  in  an  extensive  series  of 
cadavers  one  is  profoundly  impressed  with  the  ever-recurring  departure 
in  the  morphology  of  the  part  under  investigation  from  the  conventional 
or  typal  description.  This  is  particularly  applicable  to  the  gross  anatomy 
of  the  paranasal  (accessory)  sinuses.  The  primary  function  of  a  general 
text-book  of  anatomy  is  doubtless  to  describe  and  delineate  a  "typical" 
body  and  to  refer  to  a  few  variants.  It  is  obviously  impossible  to  do 
much  more  within  the  scope  of  a  single  volume.  To  visualize  and  under- 
stand the  anatomy  of  a  typical  body  is  probably  also  the  primary  function 
of  a  medical  student  in  his  initial  work  in  human  anatomy. 

Unfortunately,  however,  while  there  may  be  a  "typical"  gross  form 
for  regions,  organs  and  structures,  it  is,  strictly  speaking,  not  often 
encountered  in  nature.  The  typical  is  ideal  and  the  region,  organ,  etc., 
as  regards  shape,  size,  relations,  configuration,  etc.,  very  commonly  in 
their  actual  or  real  anatomy  are  variants.  It  is,  therefore,  of  the  greatest 
importance  that  the  student  early  recognizes  the  very  common  and  con- 
stant anatomic  variations  that  beset  the  human  body.  All  that  the  ob- 
servant student  need  do  is  to  witness  the  dissection  of  a  series  of  cadavers 
to  have  impressed  upon  him  that  there  is  no  fixed  and  unalterable  type 
in  very  many  of  the  parts  of  the  human  body.  Unfortunately,  however, 
some  students  never  get  beyond  the  belief  and  thought  that  every  struc- 
ture and  organ  and  region  conform  to  an  arbitrary  and  fixed  normal, 
and  if  there  is  a  slight  digression  from  the  conventional  text-book  descrip- 
tion the  term  "anomaly  "  is  applied.  With  this  erroneous  and  unfortunate 
belief  they  go  forth  into  the  practice  of  medicine:  To  them  the  appendix 
is  and  must  always  be  in  the  right  iliac  fossa;  every  frontal  sinus  invades 
the  vertical  portion  of  the  frontal  bone  and  if  not,  there  is  no  frontal  sinus 
present;  every  liver  has  the  same  sized  and  shaped  left  lobe  and  bears 
a  constant  topographic  relationship  to  the  ventral  abdominal  wall;  all 
stomachs  conform  to  a  single  shape;  every  transverse  colon  crosses  from 
right  to  left  at  a  specified  plane;  the  ethmoidal  air  cells  are  limited  to  the 
ethmoid  bone;  etc.,  etc.  The  far-reaching  and  direful  effects  of  such 
faulty  conceptions  of  the  anatomy  of  the  human  body  are  so  obvious  that 
they  need  not  be  discussed  here.  It,  of  course,  goes  without  saying  that 
one  must  primarily  have  a  fundamental  understanding  of  the  ground 


xxii  INTRODUCTION 

plan  of  the  human  body;  however,  it  cannot  be  gainsaid  that  one  should 
be  equally  cognizant  of  anatomical  departures  therefrom. 

Despite  that  the  actual  anatomy  of  a  region  or  part  is  not  infre- 
quently a  variant  of  the  ideal  or  typal  form  (if  there  really  be  such)  it  is 
possible  in  many  instances  to  establish  normal  anatomic  groups  or  types. 
This  is  of  decided  advantage  over  the  method  of  taking,  for  example,  a 
series  of  five  hundred  or  a  thousand  dissections  and  establishing  from  them 
a  composite  form  and  accepting  it  as  the  typical  or  ideal  anatomy  for  the 
region  or  organ. 

In  a  general  way  only  should  physicians  and  surgeons  accept  a  so- 
called  typal  or  ideal  form  in  gross  anatomy.  Initially,  of  course,  in  the 
study  of  a  patient  all  regions  and  organs  must  needs  be  approached  in 
large  measure  from  the  viewpoint  of  an  "average  anatomy"  despite 
the  fact  that  relatively  few  specimens  wholly  conform  to  it.  Fortu- 
nately, rcentgenology  has  come  to  the  aid  of  the  physician  and  surgeon 
in  the  determination  and  delineation  of  anatomic  conformations.  Ad- 
mittedly very  many  variations  are  insignificant  and  can  be  ignored 
in  the  practical  field  despite  the  fact  that  they  may  be  of  interest  and 
of  great  value  to  the  student  of  embryology  and  morphology.  How- 
ever, it  is  a  matter  of  grave  concern  to  the  physician  and  surgeon  that 
many  important  normal  variations  and  anomalies  must  be  dealt  with 
continually.  It  is,  therefore,  clearly  obvious  that  the  adherence  to  a  single 
fixed  and  arbitrary  normal  is  fraught  with  danger;  since  with  variations 
come  altered  size,  altered  shape,  altered  anatomical  relations.  Morpho- 
logical variation  must  necessarily  have  an  important  bearing  on  physical 
diagnosis,  pathology,  clinical  medicine,  and  surgery.  Indeed,  the  "ana- 
tomic type"  always  looms  up  before  the  man  in  the  practical  field  as  an 
important  factor  in  treatment  and  prognosis. 


I-GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 


THE  NOSE,  PARANASAL  SINUSES,  NASO 
LACRIMAL  PASSAGEWAYS 

AND 

OLFACTORY  ORGAN 
IN  MAN 


CHAPTER  I 

GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 
THE  PROTON  AND  RUDIMENT 

The  proton1  of  the  nose  and  the  peripheral  olfactory  organ  is  a  paired 
convex  area  of  the  cranial  ectoderm  nea'r  the  location  of  the  closed  an- 
terior neuropore,  and  the  rudiment  or  anlage  of  the  organ  is  represented 
by  a  cellular  thickening  of  the  corresponding  epithelium  (sensory  epithe- 
lium). 

The  characteristic  epithelium  of  the  olfactory  placodes  or  nasal 
areas  is  recognizable  as  early  as  the  third  week  of  embryonal  life  (4  to 
5  mm.  embryos).  At  first  the  sensory  epithelium  of  the  placodes  merges 
imperceptibly  with  the  thin  (o.oi  mm.)  surrounding  head  epithelium, 
later  thickening  with  sharp  delimitation.  These  thickened  (0.04  to 
0.05  mm.)  ectodermal  placodes  are  situated  on  both  sides  (bilaterally) 
on  the  ectal  surface  of  the  wall  of  the  forebrain,  immediately  cephalic  to 
the  primitive  oral  fossa  (Fig.  i). 

THE  NASAL  PITS 

During  the  fourth  week  (6  to  7  mm.  embryos)  the  nasal  areas  be- 
come passively  depressed  by  a  positive  increase  in  the  thickness  of  the 
surrounding  mesoderm  which  pushes  the  overlying  ectoderm  into  relief. 

1  The  term  proton  .(wpuro  j,  first)  is  here  used  to  apply  to  that  portion  of  the  indifferent  surface 
ectoderm  destined  to  establish  the  olfactory  rudiment  or  anlage.  Proton  is  not  infrequently 
used  in  a  synonymous  sense  with  rudiment  and  anlage. 

3 


GENERAL  EMBRYOLOGY  AND   DK\  I.I.OPMENT 


In  this  manner  each  olfactory  placode  becomes  surrounded  by  a  fold 
which  is  well  developed  medially  and  laterally,  but  deficient  ventro- 
caudally  (Fig.  i). 

Frontonasal,  Nasal,  and  Maxillary  Processes. — The  depressed  nasal 
areas  become  the  nasal  pits  and  are  separated  by  a  broad  mass  of  tissue 
—the  frontonasal  (frontal)  process.  As  the  pits  deepen  they  separate  in 
a  sense  the  caudal  portion  of  the  frontonasal  process  into  medial  and 
lateral  parts — the  rudiments  of  the  medial  and  lateral  nasal  processes. 
Indeed,  the  latter  processes  have  their  precursors  in  the  low  folds  of 
meso-ectodermal  tissue  which  isolate  the  nasal  areas.  During  the  latter 
part  of  the  fourth  week,  probably  a  bit  later,  the  median  portion  of  the 


Olfactory  jolacode 
(nasal 


'tfasofrontal  process 


PIG.  i. — Section  through  the  head  of  a  human  embryo  aged  approximately  3  weeks.  The  sec- 
tion shows  the  olfactory  placodes  sharply  delimited  from  the  surrounding  head  ectoblast.  Redrawn 
from  Kollmann. 

frontonasal  process  undergoes  further  differentiation  into  a  mesial  or 
unpaired  part  and  two  lateral  or  paired  parts.  The  latter  are  more 
specifically  the  medial  nasal  processes  or  the  globular  processes  of  His, 
and  they  form  the  immediate  medial  boundaries  of  the  nasal  pits.  The 
lateral  portions  of  the  frontonasal  projection  grow  caudally  and  form 
the  lateral  nasal  processes — the  immediate  lateral  boundaries  of  the  nasal 
pits  or  the  primitive  (primary)  lateral  nasal  walls. 

At  this  stage  of  development  the  maxillary  processes  of  the  first  or 
mandibular  arches  grow  ventrally  and  medially  and  abut,  later  fuse  with 
the  medial  nasal  processes.  The  fusion  takes  place  from  within  outward, 
i.e.,  from  the  depth  toward  the  surface,  and  closes  in  the  superior  bound- 


FRONTONASAL,  NASAL  AND  MAXILLARY  PROCESSES  5 

ary  of  the  primitive  oral  cavity  and  at  the  same  time  early  shuts  off  the 
cleft  of  communication  between  the  nasal  pits  and  the  oral  cavity.  The 
coalescence  of  the  maxillary  processes  with  the  medial  nasal  processes 
forms  the  primitive  or  primary  inferior  boundary  of  the  nasal  pits.  Sub- 
sequently, however,  the  extensions  of  the  lateral  nasal  processes  medially 
and  ventrally  above  the  maxillary  processes  meet  and  fuse  with  the  medial 
nasal  processes  to  form  the  immediate  definitive  inferior  boundary  of  the 


/ 


Naris 


/ 


ffedicd  7  ijusal  process 

Primitive   ckoatt(c  Globular  process 

'location  for) 

organ 


XafaraJ,  na&d  process 

Maxillary  process 

FIG.  2.  —  Drawing  of  a  reconstruction  by  the  author  of  the  face  region  of  a  human  embryo  aged 
35  days,  illustrating  the  several  embryologic  processes  and  their  coalescence  in  the  formation  of  the 
early  nasal  fossae.  X  39. 

nasal  pits.  Fusion  takes  place  also  laterally  between  the  maxillary  and 
the  lateral  nasal  processes  in  the  obliteration  of  the  naso-optic  furrow 
(Fig.  2). 

For  a  brief  time  the  lines  of  fusion  of  the  maxillary  and  the  lateral 
nasal  processes  with  the  medial  nasal  processes  are  represented  by  strands 
of  ectodermal  tissue.  These  ectodermal  fusion-lines  or  plates  soon  disap- 
pear ventrally  and  cranially  and  are  replaced  by  indifferent  mesenchyme  ; 
that  is,  the  mesenchymal  tissue  of  the  maxillary  and  lateral  nasal  proc- 
esses becomes  continuous  with  that  of  the  medial  nasal  processes. 


GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 


foss*. 


tvsiott  complete 
(epif/telmm  lost) 


fusion 


processes 
Hedial  Ttasd,  process 


FIG.  4. 


?f axillary  process 


FIG.  5. 


PIGS.  3-5-Photo 


on^crographs  of  frontal  sections  of  the  head  of  an  embryo  aged  35  days.     (Human 
ryo.    INO.    26,    Cornell    Umversrty  series,    slides    19   and   20.) 


PRIMITIVE  NASAL  FOSSyE 


7 


Fusion  in  this  manner  becomes  permanent  and  absolute.  Persistent 
eipthelial-cell  masses  may  later  in  extrauterine  life,  or  before,  give  rise  to 
epithelial  pearls  and  cysts.  Farther  dorsally  the  ectodermal  tissue  does 
not  wholly  disappear  for  some  time,  strands  remaining  between  the  abut- 
ting processes.  In  these  positions  the  primitive  choanas  (primitive 
posterior  nares)  become  established  ultimately  and  the  ectoderm  of  the 
nasal  pits  then  becomes  continuous  with  that  of  the  oral  cavity  (Figs. 
3,  4,  5  and  6). 


Primitive  choaim 
{petition  for) 


Narit 


Primitive  palate 


FIG.  6.  —  Drawing  of  a  reconstruction  by  the  author  of  the  left  nasal  fossa  of  a  human  embryo 
aged  35  days  (Embryo  No.  6,  see  Fig.  2".  Especially  note  the  simple  lateral  nasal  wall  at  this  period 
and  the  blind  termination  of  the  nasal  fossa  dorsally.  X  72. 

[THE  PRIMITIVE  (PRIMARY)  NASAL  FOSS.E 

Thirty-five-day  embryos  show  that  the  nasal  pits  have  deepened 
sufficiently  to  partake  of  the  nature  of  cleft-like  fossae.  The  olfactory 
organ  is  now  represented  by  two  blindly-ending  epithelial  pouches  lying 
in  the  mesenchymal  tissue  just  above  the  oral  cavity.  The  fossae  com- 
municate freely  with  the  exterior  by  means  of  the  nares  (anterior  nares), 
but  in  the  absence  of  choanae  (posterior  nares)  end  blindly  at  their  dorsal 
and  inferior  termination.  They  are  widely  separated  at  this  time  by 
the  thick  frontonasal  process.  Reference  to  a  35-day  embryo  indicates 
the  simplicity  of  the  lateral  nasal  wall  at  this  time  —  an  even  and  un- 
broken surface  presents  for  study.  The  medial  or  septal  wall,  on  the 

Particularly  note  the  manner  of  fusion  of  the  embryonic  processes  in  the  obliteration  of  the  com- 
munication between  the  nasal  fossae  and  the  oral  cavity.  In  Fig.  5  on  both  sides  the  two  layers  of 
epithelium,  oral  and  nasal,  have  become  attenuated  and  thinned  out  to  represent  single  layers  of 
cells  —  the  bucconasal  membranes.  The  latter  ultimately  rupture  to  establish  the  primitive  choanae. 
X  35- 


GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 


Epithelial  plugs  occlud 
ing  nares 


Septum  nasi 


FIG.  7. 


Organon  vomero- 
nasale  (Jacobsoni) 


P.  pal. 


FIG.  10. 


Eth.foU      , 


PIG.  ii.  FIG.  12. 

FIGS.  7-12. — Photomicrographs  of  frontal  sections  of  the  head  of  an  embryo  aged  43  days.     (Human 
embryo,  No.  3,  Cornell  University  series,  sections  406,  380,  365,  360,  350,  325-) 


BUCCONASAL  MEMBRANES  AND  PRIMITIVE  CHOAN.E 


contrary,  is  more  complicated  owing  to  the  rudiment  of  the  vomeronasal 
organ  of  Jacobson,  which  is  indicated  by  a  slight  groove  overhung  by  a 
mucosal  fold  (Fig.  6). 

, Cerebral  vesicle, 

i 
"X  x  /     Upper  lip(mednasproc) 

x>s  /  /         ,  Upper 'lipfmaxproc] 


Prim,  ifave  cJioanae t 

Premax.fmed.  tiasproc.) 

Alveolus  (maxproc.) 


Palatifie  process 


Roof  of  pharynx. 


Prim  i  five  palate 

(•Sept. portion.  7nxd.7ias.proc.) 


ffazil/ary  process 


PIG.  13.— Reconstruction  of  the  face  and  palate  regions  of  a  human  embryo  at  the  beginning  of 
the^  2d  month.  Especially  note  the  primitive  palate  and  the  early  palatine  processes  which  are 
beginning  to  grow  toward  the  mid-line  in  anticipation  of  the  definitive  palate.  (Redrawn  from 
Keith  after  Kollmann.) 

The  Bucconasal  Membranes  and  the  Primitive  Choanae  or  Posterior 
Nares. — The  dorsal  growth  or  extension  of  the  blind,  pouch-like  primi- 
tive nasal  fossae  meets  the  ectoderm  of  the  oral  fossa.  One  now  finds  in 


Note  the  plugging  of  the  nares  in  photograph  7 ;  moreover,  that  the  nasal  conchae  as  illustrated  in 
photographs  8-1 1  have  no  cartilage  in  them  at  this  age.  The  mesenchymal  tissue  is,  however,  under- 
going condensation  in  anticipation  of  cartilage  in  the  region  of  the  nasal  septum  and  the  lateral  nasal 
walls.  Note  also  the  relation  of  the  tongue  to  the  palatal  processes.  X  12.3. 

P.  pal.    =  processus  palatinus;  Eth.  fold    =  ethmoidal  fold;  Max.  fold    =  maxillary  fold. 


10  GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 

these  positions  the  bucconasal  membranes  composed  of  two  layers  of 
abutting  epithelium  (nasal  and  oral),  separating  the  dorsal  portion  of  the 
primitive  nasal  fossae  from  the  oral  cavity  (10  mm.  embryos).  In  35-  to 
38-day  embryos  the  membranes  are  so  attenuated  that  rupture  usually 
ensues  and  the  primitive  choanae  (primitive  posterior  nares)  are  thus 
established,  and  with  them  communication  between  the  nasal  fossae  and 
the  oral  cavity.  Lack  of  rupture  of  the  bucconasal  membranes  leads  to 
atresia  of  the  choanae,  a  condition  occasionally  observed  in  fetuses  and 
in  the  newborn.  Secondary  blocking  of  previously  patent  choanal  aper- 
tures due  to  epithelial  overgrowth  has  been  observed  by  the  writer. 


Epithelial    plug 


FIG.   14. — Photomicrograph  of  a  frontal  section  through  the  ventral  portion  of  the  nose  of  a  human 

embryo  aged  49  days.     (Embryo  No.  28,  Cornell  University  series,  slide  40.) 
Especially  note  the  epithelial  plugs  occluding  the  nares.       X  19. 

The  primitive  choanae  do  not  correspond  in  position  to  the  definitive 
choanae.  The  latter  are  placed  farther  dorsad  and  are  established  in  the 
third  month  when  the  definitive  palate  is  completed.  The  primitive 
choanae  are  located  well  in  advance  of  the  buccal  pituitary  outgrowth  in 
the  roof  of  the  mouth  and  are  separated  by  the  primitive  or  primary 
nasal  septum  (Figs.  5,  6  and  13). 

The  Nares  (anterior  nares). — When  first  formed  the  nares  communi- 
cate freely  with  the  exterior  and  their  embryological  anatomy  is  essentially 
that  of  the  early  nasal  pits.  The  luminae  of  previously  patent  nares  in 
very  many  instances  become  temporarily  obstructed  by  a  marked  pro- 
liferation of  the  epithelial  cells.  In  some  cases  the  closure  is  absolute,  in 


PRIMITIVE  PALATE  1 1 

others  deviating  passageways  exist.  As  pointed  out  by  the  writer  in  an 
earlier  publication1  the  plugging  is  rather  common  from  the  fortieth  to 
the  sixtieth  day  of  embryonic  life.  Later  there  is  a  solution  of  the  closure 
by  degeneration  of  the  central  masses  and  by  an  active  shedding,  and  the 
nares  are  again  open  to  the  exterior.  As  evidence  of  shedding,  one  often 
finds  shreds  of  epithelial  masses  protruding  from  the  nares.  Lack  of 
solution  of  the  closure  produced  by  these  epithelial  plugs  leads  to  an  atre- 
sia  of  the  nares.  The  rniisses  may  become  organized,  as  is  attested  by 
the  membranous  and  bony  atresias  and  stenoses  of  the  nares  that  are 
encountered  (Fig.  14). 

The  Primitive  Palate. — Fusion  of  the  maxillary  and  lateral  nasal  proc- 
esses with  the  medial  nasal  processes  and  the  rupture  of  the  bucconasal 


Septum,  nasi, 
liitgrzux, 
Cauiwit.  orts  ---' 


FIG.   15. — Photograph  of  a  frontal  section  through  the  head  of  an  embryo  aged  43  days.     (Embryo 

No.  3.)       X  15- 

membranes  in  the  establishment  of  the  primitive  choanae  or  posterior 
nares  delimit  for  the  first  time  the  primitive  palate.  The  latter  presents 
a  facial  and  an  oral  portion,  the  former  giving  rise  to  the  upper  lip  and 
the  latter  to  the  premaxillary  plate.  It  has  been  established  that  the 
mesoderm  of  both  the  facial  and  the  oral  portions  is  a  derivative  from 
the  maxillary  and  medial  nasal  processes,  the  lateral  nasal  process  par- 
ticipating only  at  the  caudal  border  of  the  naris  (anterior  naris),  e.g., 
the  middle  portion  of  the  primitive  palate  is  derived  from  the  medial  nasal 

'Jour.  Morph.,  Vol.  21,   1910. 


12 


GENERAL  EMBRYOLOGY  AND   DEVELOPMENT 


process,   the  dorsolateral  portion  from  the  maxillary  process,  and  the 
ventrolateral  portion  from  the  lateral  nasal  process  (Figs.  6  and  13). 

The  Definitive  Palate. — The  first  step  in  the  production  of  the  defi- 
nite palate  is  the  appearance  of  the  palatal  ridges.  These  are  wedge- 
shaped  processes  which  grow  caudally  and  somewhat  medially  from  the 
medial  sides  of  the  maxillary  processes.  The  palatal  processes  appear 
from  the  forty-fifth  to  the  forty-eighth  day  of  embryonic  life.  They  at 
first  hang  almost  vertically  toward  the  mouth  cavity,  on  either  side  of 


Orbita 


Processes  palatinus 


Cleft  communicating 

between  the  nasal  and 

oral  carilie*  before 

completion  of  the  de- 
finitive palate 

FIG.  16. — Frontal  section  through  the  nasal  fossae  of  a  human  embryo  aged  49  days.  (Embryo 
12  H.)  Especially  note  that  the  palatal  processes  have  assumed  a  horizontal  direction  in  anticipa- 
tion of  the  completion  of  the  definitive  palate.  Moreover,  note  that  the  nasal  conchas  do  not  have 
cartilage  in  them  at  this  time.  X  28. 

the  tongue,  and  extend  from  the  line  of  union  between  the  medial  nasal 
and  the  maxillary  processes  where  they  are  continuous  with  the  primi- 
tive palate,  dorsad  to  the  wall  of  the  pharynx  where  they  are  continuous 
with  the  palato-pharyngeal  folds.  The  palatal  processes  limit  the  lateral 
walls  of  the  cavum  nasi  caudally  (Fig.  8). 

For  a  relatively  brief  time  the  tongue  is  between  the  palatal  processes, 
the  latter  extending  below  the  level  of  the  dorsum  of  the  tongue.     Subse- 


DEFINITIVE  PALATE  13 

quently  the  tongue  seemingly  sinks  and  comes  to  occupy  a  lower  position 
in  the  mouth  cavity.  Concomitant  with  this  change  of  the  tongue  the 
palatal  processes  become  passively  rather  than  mechanically  rotated,  due 
to  an  unequal  growth,  from  an  almost  vertical  and  sagittal  plane  to  a 
horizontal  plane  and  subsequently  meet  in  the  median  sagittal  plane 
over  the  tongue — fusion  taking  place  from  before  backward  along  the 
opposed  edges.  Nests  of  epithelial  cells  may  persist  between  the  fused 
elements  giving  rise  later  to  epithelial  pearls  or  even  to  cysts.  The  dorsal 
parts  of  the  folds  maintain  their  original  direction.  Subsequently  bony 
plates  extend  into  the  membranous  palatal  processes  to  form  the  greater 


Etk.  fold 


Naris— 


Max.  fold 


PIG.  17. — Drawing  of  a  reconstruction  of  the  lateral  wall  of  the  nasal  fossa  of  an  embryo  aged  43 
days.  (Human  embryo  No.  3,  Cornell  University  series,  section  300-420  inclusive.)  Particularly 
note  that  the  palatal  process  (P.  pal.)  hangs  in  the  sagittal  plane  at  this  time.  The  maxillary  fold 
(Max.  fold),  the  rudiment  of  the  inferior  nasal  concha,  occupies  the  greater  portion  of  the  lateral 
nasal  wall  while  the  ethmoidal  fold  (Eth.  fold),  the  rudiment  or  anlage  of  the  ethmoidal  nasal  conchae,  is 
relatively  inconspicuous.  X  24.  (After  J.  P.  5.) 

portion  of  the  hard  palate.  Dorsally  these  plates  are  wanting  and  mus- 
cular tissue  extends  into  the  processes,  giving  origin  to  the  soft  palate 
and  to  the  uvula.  In  the  formation  of  the  definitive  hard  palate  a 
substantial  portion  of  the  primitive  buccal  cavity  is  isolated  and  made 
part  of  the  nasal  cavity  (Figs.  15,  16,  17,  18  and  19). 

As  was  previously  pointed  out,  the  mesial  nasal  processes  unite 
superficially  to  form  the  central  part  of  the  upper  lip  and  philtrum  and 
conjointly  extend  dorsad  in  the  roof  of  the  stomodeum  to  form  the  inter- 


14  GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 

maxillary  process  (the  greater  portion  of  the  primitive  palate,  vide  supra). 
The  intermaxillary  process  projects  farthest  dorsad  in  the  median  plane 
and  by  its  lateral  borders  abuts  with  the  lateral  nasal  processes  ventrally 
and  with  the  maxillary  processes  farther  dorsally.  At  the  dorsal  ends 
of  the  planes  of  contact  fusion  is  imperfect,  leading  to  the  formation  of 
the  incisive  foramina  (anterior  palatine  canals).  The  latter  transmit  (a) 
nerves  and  vessels  which  course  between  the  mucosae  of  the  oral  and  nasal 
cavities  and  (b)  the  nasopalatine  canals  (canals  of  Stenson)  which  early 
connect  the  nasal  and  oral  cavities,  but  in  later  life  generally  become  oblit- 


Concha  nasal  is 
supremo,  I 

Concha  nasalis 
superior 

Concha  nasalis 
media 


Concha  nasalis 
inferior 


Processus 
palatinus 


FIG.    1 8. — Drawing  of  a  reconstruction  of  the  lateral  wall  of  the  nasal  fossa  of  an  embryo  aged  49 

days.     (Human  embryo  No.  28,  Cornell  University  series,  slides  40-51  inclusive.) 
Especially  note  that  the  palatal  process  has  now  assumed  a  horizontal  position  in  anticipation  of 
the  completion  of  the  palate.     Moreover,  note  that  the  ethmoidal  fold  has  enlarged  and  become  dif- 
ferentiated into  a  number  of  ethmoidal  conchas.       X  26.      (After  J.  P.  5.) 

crated,  at  least  at  their  oral  extremities  (see  page  76).  Little  of  the  primi- 
tive palate  is  so  located  as  to  participate  in  forming  the  adult  palate  proper. 
The  Definitive  Choanae  (posterior  nares). — Coincident  with  the 
growth  of  the  facial  region  and  the  formation  of  the  palatal  processes  the 
primitive  or  primary  choanae  become  elongated  and  form  slit-like  pas- 
sageways between  the  nasal  and  oral  cavities  (Fig.  13).  The  continued 
growth  and  the  ultimate  fusion  from  before  backward  in  the  mid-sagittal 


DEFINITIVE  CHOAX/E 


plane  of  the  palatal  processes  in  the  formation  of  the  secondary  palate, 
and  the  buccal  and  pharyngeal  extensions  of  the  primary  nasal  septum, 
force  the  primitive  or  primary  choanae  to  undergo  a  steady  dorsal  migra- 
tion until  communication  with  the  cephalic  and  ventral  termination  of 
the  pharynx  is  established.  This  connection  locates  the  definitive  choanae 


Concha  nasalis 
suprema  II 

Concha  nasalis 
suprema  J 

Concha  nasalis 
superior 


Concha  -nasa/is 
media 

Lobtilus 

Concha  nasal  if 
inferior 


Definitive  palate 


FIG.   19. — Drawing  of  a  reconstruction  of  portion  of  the  right  wall  of  the  nasal  cavity  of  an  embryo 

aged  105  days.      (Human  embryo  No.  43,  Cornell  University  series,  slides  1-90  inclusive.) 
Note  that  the  definitive  palate  is  now  completed  and  that  the  choana  has  assumed  its  final  posi- 
tion.    Ths  ethmoidal  field  has  differentiated  into  four  nasal  conchae.     Especially  note  the  marked 
lobule  in  the  region  of  the  knee  of  the  concha  nasalis  media.      X  9-5-     (After  J.  P.  S  ) 

or  posterior  nares.  As  the  primary  choanae  migrate  dorsally,  due  to  the 
fusing  of  the  palatal  processes,  the  nasal  septum  fuses  with  the  mid- 
palatal  ridge  to  divide  the  nasal  cavity  into  the  right  and  left  nasal  fossae. 
Here,  too,  the  division  and  fusion  take  place  from  before  backward. 


l6  GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 

The  Primary  Nasal  Septum  (the  septum  nasi  primum) . — The  mesial 
nasal  processes — the  symmetrical  mesial  and  caudal  extensions  of  the 
frontonasal  process —  fuse  together  and  form  the  middle  third  of  the  upper 
lip,  the  intermaxillary  process,  and  the  primary  nasal  septum  between 
the  primitive  (primary)  nasal  fossae.  Moreover,  when  the  primitive  nasal 
fossae  establish  communication  with  the  roof  of  the  buccal  cavity  by  the 
formation  of  the  primitive  choanae,  it  is  the  primary  nasal  septum  that  in- 
tervenes between  these  apertures  as  a  wide  plate  in  the  roof  of  the  mouth. 

The  Secondary  Nasal  Septum  (the  septum  nasi  secundum). — During 
the  latter  part  of  the  second  month  of  fetal  life  after  the  primitive  choana? 
are  formed,  the  primary  nasal  septum  begins  to  grow  buccalward  and 
pharyngealward  until  the  aperture  of  the  buccal  pituitary  outgrowth  is 


FIG.   20. — Model  of  the  nasal  cavity  of  a  49-day  human  embryo.      Particularly  note  the  connection 

(nasobuccal  cleft)  between  the  nasal  fossae  and  the  mouth  cavity. 

M.  \*.  S.  I.    =  Meatus  nasi  supremus  I;  M.  N.  S.    =  Meatus  nasi  superior;  M.  N.  M.    =  Meatus 
nasi  medius;  M.  N.  I.   =  Meatus  nasi  inferior. 

included  in  its  dorsocranial  border.  Coincidently,  the  nasal  fossae  are 
elongated  in  the  ventrodorsal  plane,  the  definitive  palate  is  completed, 
and  the  definitive  choanae  are  established  in  the  region  of  the  naso-pharynx 
(end  of  third  month).  Moreover,  the  secondary  nasal  septum  has  ex- 
tended sufficiently  buccalward  to  fuse  with  the  mid-palatal  ridge,  which 
it  does  from  before  backward,  in  the  division  of  the  general  nasal  cavity 
into  the  definitive  nasal  fossae. 


DEFINITIVE  NASAL 

THE  DEFINITIVE  (SECONDARY)  NASAL  FOSSAE 

With  the  completion  of  the  boundaries,  that  is,  the  medial  and  lateral 
walls,  the  roof  and  floor,  and  the  choanal  apertures,  the  nasal  fossae  are 
not  limited  to  their  primitive  site,  but  have  incorporated  a  goodly  portion 
of  the  buccal  cavity  on  the  nasal  side  of  the  hard  palate  and  in  a  sense  they 
pass  into  a  secondary  developmental  stage.  It  is,  therefore,  suitable  to 


FIG.  21. — Frontal  section  of  the  nose  of  a  human  embryo  aged  120  days.  On  one  side  the  section 
is  through  the  region  of  the  ostium  maxillare  and  on  the  other  dorsal  to  it.  Xote  the  fusion  on  the 
left  side  between  the  processus  uncinatus  and  one  or  more  frontal  conchae.  This  causes  the  infundi- 
bulum  ethmoidale  to  end  blindly  ventrocephalically.  Farther  dorsad  as  illustrated  on  the  right  side 
the  infundibulum  ethmoidale  is  of  course  in  wide  communication  with  the  meatus  nasi  medius  via  the 
hiatus  semilunaris.  X  10. 

F.  cr.  ant.  =  Fossa  cranii  anterior;  Inf.  eth.  =  Infundibulum  ethmoidale;  O.  m.  =  Ostium 
maxillare;  S.  max.  =  Sinus  maxillaris;  B.  eth.  =  Bulla  ethmoidalis;  H.  sem.  =  Hiatus  semilunaris; 
Proc.  unc.  =  Processus  uncinatus;  Os  =  maxilla  undergoing  ossification. 

speak  of  the  primitive  nasal  fossae  and  the  incorporated  portion  of  the 

buccal  cavity  as  conjointly  forming  the  definitive  or  secondary  nasal  fossae. 

It  is  during  the  secondary  phase  of  development  that  the  nasal  bound- 


iS  (;I:M:R\I.  EMBRYOLOGY  AND  DEVELOPMENT 

aries  continue  their  chondrification  and  ossification,  that  the  elements 
entering  into  the  boundaries  attain  definition.  Moreover,  the  previously 
simple  lateral  nasal  wall  undergoes  profound  metamorphosis  in  the  forma- 
tion of  the  appendages  which  ultimately  characterize  its  surface;  the  para- 
nasal  sinuses  begin  to  take  form  and  position,  while  the  septal  wall,  on  the 
contrary,  becomes  relatively  more  simple  as  its  definitive  form  is  reached. 
It  must,  however,  be  understood  that  there  is  no  sharp  border  line 
between  the  primitive  and  definitive  growth  periods  of  the  nasal  fossa?; 
rather  that  growth  processes  begun  in  the  primitive  period  are  continued 
and  carried  to  fruition  in  the  secondary  period.  In  a  sense,  during  the 
primitive  stage  of  development  the  foundation  and  superstructure  of  the 
nose  are  formed  and  in  the  subsequent  period  the  interior  and  exterior  are 
molded  and  modeled  in  the  formation  of  many  secondary,  yet  complex 
and  important  structures. 

THE  LATERAL  NASAL  WALL 

The  lateral  wall  of  the  nasal  fossa  of  a  35-day  embryo  gives 
no  evidence  whatsoever  of  its  later  complexity.  Indeed,  the  medial  or 
septal  wall  is  more  complicated  at  this  stage  of  development  owing  to 
the  vomeronasal  organ  which  is  a  prominent  structure  in  the  early  embryo. 
There  is  an  inherent  tendency  for  the  nasal  cavity  early  and  rapidly  to 
increase  its  surface  area.  Even  before  the  first  appearance  of  the  palatal 
processes  as  limiting  shelves  for  the  nasal  fossae  caudally,  the  lateral  walls 
of  the  fossae  have  begun  in  a  simple  manner  the  complex  configuration 
which  ultimately  characterizes  them.  The  complexity  in  the  anatomy 
of  the  lateral  wall  is  due  to  the  development  of  the  major  nasal  conchae 
(turbinates),  the  minor  (accessory)  nasal  conchae,  the  major  nasal  meatuses, 
the  secondary  nasal  meatuses,  and  the  paranasal  (accessory)  chambers. 

The  portion  of  the  inferior  nasal  meatus  that  lies  dorsal  to  the  incisive 
canal,  together  with  the  space  immediately  behind  the  dorsal  extremities 
of  the  ethmoidal  conchae  as  far  back  as  the  ostium  of  the  auditive  tube 
(Eustachian  tube) ,  is  derived  from  the  primitive  buccal  cavity  of  the  fetus, 
having  become  isolated  by  the  formation  of  the  definitive  palate.  The 
dorsal  extension  of  some  of  the  nasal  conchae  toward  the  choana  beyond 
the  confines  of  the  primary  nasal  fossa  is  purely  secondary. 

(A)  The  Major  Nasal  Conchae  (endoturbinals)  and  Meatuses.— 
The  co'nchal  or  turbinal  apparatus  of  the  human  nose  is  much  reduced,  and 
its  development  takes  place  entirely  in  the  region  of  the  sensory  epithe- 
lium, e.g.,  in  the  primitive  nasal  cavities.  The  conchae  arise  on  both  the 
lateral  and  medial  walls  of  the  nasal  fossa:  The  agger  nasi  (naso turbinal) 


MAJOR  NASAL  CONCHA  AND  MEATUSES 


and  the  concha  nasalis  inferior  (maxilloturbinal)  arise  from  the  lateral 
wall,  and  the  conchae  of  the  ethmoid  region  (ethmoturbinals)  arise  in  part 
(J.  P.  Schaeffer)1  or  wholly  (Peter)2  from  the  median  wall.  By  a  process 
of  unequal  growth  the  ethmoidal  conchae  are  transferred  wholly  to  the 
lateral  nasal  wall.  It  is,  of  course,  essential  that  appropriately  aged 
embryos  are  studied  for  the  initial  stage.  The  transference  to  the  lateral 
wall  occurs  at  an  early  time  and  this  may  mislead  the  investigator. 


FIG.  22.  PIG.  23.  FIG.  24.  FIG.  25. 

FIGS.  22-25. — Reconstructions  of  portions  of  the  lateral  nasal  wall  in  the  frontal  plane  and  at 
various  levels.  (Human  embryo,  aged  approximately  125  days.)  Fig.  22  represents  the  nasal  wall 
farthest  ventrad  and  Fig.  25  farthest  dorsad. 

le.  =  Infundibulum  ethmoidale;  Mnm.  =  Meatus  nasi  medius;  Cnm.  =  Concha  nasalis  media; 
Cni.  =  Concha  nasalis  inferior;  Sn.  =  Septum  nasi;  Cns.  =  Concha  nasalis  superior;  Be.  =  Bulla 
ethmoidalis;  Hs.  =  Hiatus  semilunaris;  Om.  =  Ostium  maxillare;  Pu.  =  Processus  uncinatus; 
S.  max.  =  Sinus  maxillaris;  Mni.  =  Meatus  nasi  inferior. 

The  mechanism  by  which  the  nasal  conchae  and  meatuses  are  ini- 
tially formed  is  variously  interpreted.  At  the  outset  it  may  be  definitely 
stated  that  in  the  conchae  of  the  human  nose  the  skeleton  is  not  the  primary 
structure  as  is  so  frequently  given.  Cartilage  does  not  grow  into  the 
primitive  (primary)  conchae,  but  develops  or  arises  within  previously 

1  Schaeffer:  The  Lateral  Wall  of  the  Cavum  Nasi  in  Man  with  Especial  Reference  to  the  Various 
Developmental  Stages,  Jour,  of  Morph.,  Vol.  21,  1910. 

2  Peter:  Die  Entwicklung  der  Nasenmuscheln  bei  Mensch  und  Saugetiern,  Archiv  f.  mikroskop. 
Anatom.,  Bd.  79,  1912. 


20 


GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 


established  conchal  rudiments  or  anlages  composed  of  epithelium  and  sub- 
jacent indifferent  mesenchyme.  In  other  words,  the  conchae  or  turbinates 
are  not  primarily  produced  by  inpushings  of  the  nasal  wall  due  to  carti- 
laginous strands  or  bars.  Indeed,  the  initial  conchae  are  present  before 
the  precartilage  stage  of  the  mesenchyme  (Figs.  8  to  12). 

The  Inferior  Nasal  Concha  (concha  nasalis  inferior)  and  the  Inferior 
and  Middle  Nasal  Meatuses  (meatus  nasi  inferior  et  medius). — After  a 
study  of  the  blastemal  period  and  early  development  of  these  structures, 
the  writer  is  led  to  believe  that  the  first  change  in  the  lateral  nasal  wall 
from  a  more  or  less  even  and  unbroken  surface  is  the  production  of  two 
shallow  grooves,  one  inferior  and  the  other  superior  to  the  position  of  the 


Agger 


Lobulus 


FIG.  26. — The  lateral  nasal  wall  of  a  t'erm  fetus.  Note  particularly  the  large  number  of  ethmoidal 
conchae  that  are  occasionally  differentiated.  X  1.5.  This  and  the  following  figures,  27—34,  are  after 
Schaeffer,  Journal  of  Morphology,  Vol.  21,  No.  4. 

a,  c,  e,  g,  i  =  ascending  rami  of  the  ethmoidal  meatuses;  w,  u,  s,  p,  n  =  descending  rami  of  the 
ethmoidal  meatuses;  b,  d,f,  h,  k  =  ascending  crura  of  the  ethmoidal  conchae;  v,  t,  r,  o,  tn  =  descend- 
ing crura  of  the  ethmoidal  conchae;  I  =  sinus  sphenoidalis;  x  =  incisura  retrolobularis. 

primitive  concha  nasalis  inferior  (38-  to  4O-day  embryos).  These  shallow 
grooves,  the  rudiments  of  the  meatus  nasi  inferior  and  medius,  throw  at 
once  into  slight  relief  the  greater  portion  of  the  lateral  nasal  wall  and  es- 
tablish the  initial  stage  of  the  concha  nasalis  inferior  (maxilloturbinal). 
The  indifferent  mesenchymal  tissue  contained  within  this  primitive 
fold  simultaneously  undergoes  proliferation"  and  aids  in  making  the  fold 
more  prominent.  The  mucous  membrane  over  the  fold  is  but  slightly 
thickened  at  this  time.  The  writer  is  not  in  accord  with  those  who  argue 
that  the  formation  of  a  well-developed  maxillary  fold  is  wholly  due  to 
the  formation  and  deepening  of  the  bordering  furrows.  The  formation  of 
the  shallow  furrows  is  doubtless  the  primitive  step  in  conchal  formation. 


MAJOR  NASAL  CONCHA  AND  MEATUSES  21 

However,  the  proliferation  of  the  indifferent  mesenchyme  contained  in  the 
fold  aids  materially  in  causing  the  primitive  concha  inferior  to  bulge  into 


Ascending  crural  mass 


Descending  crura  of 
ethmoidal  conchae 


FIG.   27. — The  lateral  nasal  wall  of  a  term  fetus. 

the  lumen  of  the  nasal  fossa  and  the  bordering  furrows  to  become  passively 
deeper  (Fig.  17). 

The  Ethmoidal  Concha  (conchae  ethmoidales)  and  the  Superior  and 
First,  Second  and  Third  Supreme  Nasal  Meatuses  (meatus  nasi  superior  et 

Ascending  rami  of 
meatus  nasi 

ace       g  i 


FIG.   28. — The  lateral  nasal  wall  of  a  term  fetus. 

supremae  I,  II,  III). — The  ethmoidal  fold  (rudiment  of  the  ethmoidal 
conchae)  appears  next  in  the  extreme  dorsal  and  superior  portion  of  the 


-V 


GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 


nasal  fossa  in  the  angle  formed  by  the  lateral  wall  and  nasal  septum. 
Since  the  primitive  concha  inferior  (maxillary  fold)  takes  up  the  greater 
portion  of  the  lateral  nasal  wall  at  this  time,  there  is  little  room  for  the 
primitive  ethmoidal  fold.  In  a  former  study  the  author1  concluded  that 
the  ethmoidal  fold  arose  both  from  the  septal  and  lateral  walls.  Peter,2  on 
the  contrary,  believes  that  it  arises  in  whole  from  the  septal  wall.  With 
further  and  unequal  growth  of  the  nasal  fossa  in  the  dorso-superior  direc- 
tion, the  ethmoidal  fold  passively  migrates  from  the  septal  to  the  lateral 
nasal  wall.  The  mucous  membrane  over  the  ethmoidal  fold  is,  as  a  rule, 

Ascending  rami  of 

meatus  nasi 


furrows  on  medial 
surf,  of  con.  media 


PIG.   2Q. — Ths  lateral  nasal  wall  of  a  term  fetus.      Particularly  note  the  multiple  furrows  on  the  medial 
surface  of   the   concha   nasalis  media. 

thickened.  Gradually,  in  place  of  the  single  ethmoidal  fold,  there  are 
established  rudiments  of  the  individual  ethmoidal  conchse  or  turbinates. 
The  development  of  these  conchae  proceeds  from  the  most  caudal  to  the 
most  cephalic.  One  sees  two  ethmoidal  conchae  in  embryos  aged  approxi- 
mately 48  days,  three  conchae  in  embryos  aged  95  to  100  days.  In  fetuses 
from  the  seventh  month  to  term,  one  finds  from  three  to  five  ethmoidal 
conchae  with  a  corresponding  number  of  intervening  meatuses.  After 
birth  the  ethmoidal  conchae  are  usually  reduced  in  number  by  a  coalescence 
of  the  uppermost  and  less  developed  members  with  a  resultant  obliteration 
of  the  intervening  meatuses.  When  the  usual  two  or  three  ethmoidal 
conchae  are  found  in  the  adult,  it  is  difficult  to  decide  whether  coalescence 

'Loc.  cit. 
sLoc.  cit. 


MAJOR  NASAL  CONCILE  AND  MEATUSES  23 

of  parts  (regression)  or  lessened  differentiation  (progression)  was  the  de- 
termining factor.  In  the  adult  one  rarely  finds  more  than  three  eth- 
moidal  conchae.  Therefore,  numerical  reduction  must  be  a  factor  in 
some  instances  (Figs.  26  and  146). 

Doubtless  the  personal  equation  is  an  important  factor  in  the  diverg- 
ent findings  reported  as  to  the  number  of  fetal  ethmoidal  conchae  that  are 
differentiated.  In  many  cases  the  more  cephalic  folds  are  extremely 
rudimentary  and  are  usually  overlooked  or  considered  too  small  to  be 
counted  as  ethmoidal  conchae.  The  conchae  supremae  II  and  III,  when 
differentiated,  as  a  rule  early  lose  their  identity  by  fusion,  and  in  infancy 
and  adult  life  three  ethmoidal  conchae  must  be  considered  the  typical 
number  rather  than  two  as  usually  given.  An  examination  by  the  author 


Lobuli 


Aggei 


FIG.  30. — The  lateral  nasal  wall  of~a  2io-day  fetus.     Note  especially  the  lobuli  on  the  ethmoidal 

conchae. 

of  264  infant  and  adult  specimens  showed  160  with  three  ethmoidal  con- 
chae, 98  with  two  ethmoidal  conchae,  4  with  four  ethmoidal  conchae,  and  2 
with  one  ethmoidal  concha.  The  ostium  of  the  posterior  ethmoidal  cell 
which  develops  from  the  meatus  nasi  suprema  I  is  a  good  and  reliable 
point  for  orientation  in  determining  the  presence  of  a  concha  nasalis 
suprema  I.  The  latter  is  present,  according  to  the  author's  studies,  in 
approximately  60  per  cent,  of  the  cases,  and  in  75  per  cent,  of  them  a 
posterior  ethmoidal  cell  develops  from  the  corresponding  meatus  (Fig. 
127).  The  latter  anatomical  fact  needs  explanation  by  those  who  argue 
that  two  ethmoidal  conchae  represent  the  typical  field;  especially  so  when 
one  recalls  that  the  cellulae  ethmoidales  develop  from  preformed  nasal 
meatuses. 

The  group  of  ethmoidal  conchae  and  meatuses  in  a  general  way  early 
possess  knees,  thus  giving  rise  to  ascending  and  descending  crura.       The 


24  GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 

angular  condition  lessens  as  one  passes  from  the  middle  concha  and  its 
corresponding  meatus  to  the  highest  concha  and  meatus  present.       In 

Concha  nasalis 
suprema  I 


Concha 

superior 
Concha  nasalis 

media 

Concha  nasalis 
inferior 

FIG.  31. — The  lateral  nasal  wall  of  a  ipo-day  fetus.     Especially  note  the  rudimentary  character  of 
the  concha  nasalis  superior.      X  2.3. 

fact,  the  upper  ethmoidal  conchae  are  represented  mainly  by  the  descend- 
ing crura.     Often  the  ascending  crura  are  not  at  all  differentiated,  the 


(    TG>  32.— Drawing  of  a  frontal  section  through  the  lateral  wall  of  the  nasal  cavity  in  the  region 
:hmoidal  conchae  (fetus  aged  from  7-8  months,  series  B,  slide  48).     The  concha  nasalis  in- 
ferior is  not  included  in  the  section.       X  8. 

whole  region  being  represented  by  a  general  undifferentiated  crural  mass 
(Fig.  27).     Ascending  and  descending  crura  are,  however,  constant  for  the 


LOBULES  AND  NODULES 


concha  nasalis  media  and  the  meatus  nasi  medius.  The  concha  nasalis 
superior  and  its  corresponding  meatus  also  frequently  persist  in  the  adult 
as  angular  structures.  Briefly  stated,  the  integrity  of  the  ethmoidal 
conchae  and  meatuses  is  more  or  less  dependent  upon  the  descending  or 
inferior  crura,  the  middle  concha  and  meatus  excepted. 

At  the  junction  of  the  ascending  and  descending  crura  of  the  eth- 
moidal conchae  one  commonly  finds  overhanging  lobule  formations  (Figs. 


#?:%i$' 


Supra  bullar  furrow 


Cellulae  ethmoidales 
Superior  bullar  fold 
Bullar  furrow 

Tnferinr  bu  liar  fold 


,-  —  '•  —  Infrabullar  furrow 

fold 


Infundib.  ethmoidale 
Processus  uncinatut 


Sinn*  maxillarw 


FIG.  33. — Drawing  of  a  frontal  section  of  the  lateral  wall  of  the  left  nasal  fossa  of  a  term  fetus  (series 

D,  slide  5). 
Note  the  individual  folds  comprising  the  bulla  ethmoidalis.       X  5.8. 

19  and  30),  the  most  marked  and  constant  of  which  is  found  on  the 
knee  of  the  concha  media.  The  latter  lobule  may  be  of  such  size  as  to 
lead  to  mechanical  obstruction  of  the  meatus  nasi  medius  in  the  neighbor- 
hood. This  lobule  must  not  be  mistaken  for  the  later  and  very  common 
distention  of  the  middle  concha  due  to  an  ingrowth  of  an  infundibular  or 
other  anterior  ethmoidal  cell  to  become  conchal  in  position.  Mechanical 
obstruction  of  the  meatus  may  likewise  follow,  depending  upon  the  size 


26  GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 

of  the  cell.  Secondary  nodules  frequently  form  on  each  primary  lobule 
(Fig.  30).  The  lobule  and  secondary  nodules  of  the  human  ethmoidal 
conchae  (ethmoturbinals)  are  the  homologues  of  the  rather  sharp  ventral 
projections  of  the  ethmoturbinals  of  mammals. 

The  concha  nasalis  media  often  presents  a  number  of  secondary 
furrows  on  its  medial  surface  (Figs.  28  and  29).  A  single  and  deeply  cut 
furrow  often  partially  divides  the  concha  into  halves.  Errors  are  fre- 
quently made  in  such  instances  in  considering  the  portion  inferior  to  the 
furrow  as  the  concha  media  and  the  portion  superior  as  the  concha 
superior.  Such  an  analysis  would  erroneously  make  of  the  furrow  the 
meatus  nasi  superior.  Zuckerkandl  early  made  this  error,  but  later  cor- 
rected himself.  A  few  recent  publications  continue  to  err  in  regards  to  the 
furrows  found  on  the  medial  surface  of  the  middle  concha. 

The  Nasoturbinal  (agger  nasi)  and  the  Nasal  Atrium  (atrium  nasi, 
atrium  meatus  medii). — The  nasoturbinal  appears  relatively  late  in  man 
and  is  always  extremely  rudimentary  as  compared  with  the  higher  mam- 
mals, e.g.,  rabbit,  sheep,  pig,  ox,  etc.  It  appears  as  a  slight  elevation 
cephalic  to  the  concha  inferior  (maxilloturbinal)  and  ventral  to  the  concha 
media  (ethmoturbinal).  It  develops  more  or  less  parallel  to  the  bridge  of 
the  nose.  Infundibular  cells  (anterior  ethmoidal  cells)  frequently  grow 
out  from  the  infundibulum  ethmoidale  into  the  agger  nasi  (Fig.  75)  and 
are  often  referred  to  as  agger  cells  (see  pages  221  and  223). 

The  Nasal  Atrium. — This  is  a  shallow  depression  immediately  infero- 
dorsal  to  the  nasoturbinal  or  agger  nasi  and  in  a  sense  may  be  considered 
its  related  meatus,  and  since  it  is  a  sort  of  an  antespace  to  the  middle 
nasal  meatus  is  frequently  referred  to  as  the  atrium  of  the  middle  nasal 
meatus. 

The  Olfactory  Sulcus  (sulcus  olfactorius,  carina  nasi). — This  is  a 
cleft-like  space  developed  between  the  agger  nasi  and  the  ental  surface  of 
the  dorsum  of  the  nose  (dorsum  nasi)  and  leads  from  the  nasal  vestibule 
to  the  olfactory  part  (pars  olfactoria)  of  the  nasal  fossa  (see  page  97  and 
Fig.  146). 

The  Sphenoethmoidal  Recess  (recessus  sphenoethmoidalis).— The 
sphenoethmoidal  recess  is  developmentally  related  with  the  posterior 
cupola  of  the  cartilaginous  nasal  capsule  and  is  located  cephalic  and  dorsal 
to  the  highest  ethmoidal  concha  that  may  be  differentiated  and  is  limited 
by  the  angle  formed  by  the  cribriform  plate  of  the  ethmoid  and  the  ven- 
tral surface  of  the  sphenoid.  From  its  dorsal  boundary  or  wall  develops 
the  sphenoidal  sinus  and  in  later  life  contains  the  ostium  or  aperture  of  this 
sinus  (Fig.  127). 


MINOR  NASAL  CONCHA  AND  MEATUSES  27 

Nomenclature. — From  the  foregoing  it  would  appear  that  the  general 
text-books  of  anatomy  offer  nomenclatures  sufficiently  extensive  for  adult 
conditions,  but  not  for  the  late  fetal  and  early  infantile  stages.  The  writer 
would,  therefore,  suggest  the  following  terminology  which  covers  not 
only  adult  conditions,  but  also  the  extreme  ethmoidal  differentiations 
found  in  infancy  and  late  fetal  life : 


. 


Concha  nasa/i* 
tvpremu  f 


FIG.  34. — A  frontal  section  through  the  lateral  wall  of  the  nasal  fossa  in  the  region  of  the  superior 

nasal  meatus  (7-month  fetus,  series  C,   slide  8). 
Especially  note  the  accessory  concha  of  the  superior  meatus  and  the  crista  suprema.       X  to. 


Conchce  nasales1 
Concha  nasalis  inferior 
Concha  nasalis  media 
Concha  nasalis  superior 
Concha  nasalis  suprema  I 
Concha  nasalis  suprema  II 
Concha  nasalis  suprema  III 
Agger  nasi 


Meatus  nasi 
Meatus  nasi  inferior 
Meatus  nasi  medius 
Meatus  nasi  superior 
Meatus  nasi  supremus  I 
Meatus  nasi  supremus  II 
Meatus  nasi  supremus  III 
Atrium  nasi 


(B)  The  Minor  or  Accessory  Nasal  Conchae  (ectoturbinals,  conchae 
obtectse)  and  Meatuses  or  Furrows. — Nasal  conchae  and  meatuses  or 
furrows  of  a  secondary  or  accessory  nature  are  regularly  differentiated 
and  developed  in  the  human  nasal  cavity  and  are  homologous  with  analo- 
gous structures  found  in  the  mammalia,  e.g.,  rabbit,  cat,  etc.  They  are 

1  J.  Parsons  Schaeffer:  The  Lateral  Wall  of  the  Cavum  Nasi  in  Man,  with  Especial  Reference 
to  the  Various  Developmental  Stages,  Jour.  Morph.,  Vol.  21,  No.  4,  1910. 


28 


GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 


intimately  associated  with  the  genetic  history  of  the  paranasal  (accessory) 
sinuses  and  unless  one  has  a  clear  conception  of  the  origin  and  development 
of  these  early  secondary  structures  found  in  the  middle  and  superior 
nasal  meatuses,  it  will  be  impossible  to  properly  interpret  the  early  pre- 
natal and  adult  anatomy.  Errors  are  repeatedly  made  in  the  analysis 
of  the  adult  ethmoid  labyrinth,  the  nasof rental  connections,  etc.,  because 
adult  and  late  fetal  material  alone  are  studied. 

The  accessory  nasal  conchae  and  meatuses  (folds  and  furrows)  are 
located  (i)  in  the  descending  ramus  of  the  meatus  nasi  medius,  (2)  in 
the  ascending  ramus  of  the  meatus  nasi  medius,  and  (3)  in  the  descending 
ramus  of  the  meatus  nasi  superior.  These  secondary  or  accessory  struc- 


_,  Frontal,  furrows 


frontal  folds 
(accessory  conchcw) 


free, 


Concha,  juts,  mad 


Evlla,  etk 


FIG.  35. — A  dissection  of  the  lateral  nasal  wall  of  a  term  fetus.  The  concha  nasalis  media  has  in 
large  measure  been  removed  thereby  exposing  the  accessory  folds  or  conchae  and  furrows  of  the  as- 
cending (frontal  recess)  and  descending  rami  of  the  meatus  nasi  medius.  X  2. 

tures  are  more  or  less  hidden  and  operculated  by  the  conchse  nasales 
media  and  superior: 

i.  The  Descending  Ramus  of  the  Meatus  Nasi  Medius. — Serial 
frontal  sections  of  the  nose  of  4O-day  embryos  show  that  the  lateral 
wall  of  the  meatus  nasi  medius  is  even  and  unbroken.  On  the  contrary, 
the  same  region  in  embryos  aged  from  40  to  60  days  presents  a  crescentic- 
shaped  fold  breaking  the  evenness  of  the  wall.  This  fold  is  the  rudiment 
or  anlage  of  the  processus  uncinatus  and  is  the  first  of  a  series  of  accessory 
folds  to  appear  on  the  lateral  wall  of  the  meatus  medius.  The  fold  at 
once  aids  in  forming  a  furrow  immediately  superior  to  it — the  primitive 
infundibulum  ethmoidale.  It  is  quite  probable  that  the  furrow  first  estab- 
lishes a  rudiment  and  this  in  turn  throws  into  slight  relief  a  portion  of  the 
mucous  membrane  inferior  to  it,  thus  establishing  the  anlage  of  the  pro- 
cessus uncinatus.  It  may,  however,  be  said  that  both  structures  are 


MINOR  NASAL  CONCH.E  AND  MEATUSES  29 

more  or  less  dependent  upon  each  other  in  establishing  rudiments.  The 
same  principles  are  obviously  here  involved  as  they  are  in  forming  the 
primitive  major  nasal  meatuses  and  conchse.  From  the  primitive  infundi- 
bulum  ethmoidale,  the  sinus  maxillaris  develops  its  rudiment  (65-  to  70- 
day  embryos)  in  the  form  of  an  evagination  of  the  mucous  membrane. 
This  outpouching  of  the  mucosa  aids  in  early  establishing  the  processus 
uncinatus  and  the  infundibulum  ethmoidale. 

Shortly  after  this  we  have  the  first  evidence  of  the  bulla  ethmoidalis, 
appearing  superior  and  lateral  to  the  processus  uncinatus.  The  bulla 
ethmoidalis  is  first  indicated  by  special  thickenings  (one  or  two)  of  the 
lateral  plate  of  cartilage — the  cartilaginous  thickenings  appearing  on  its 
medial  surface.  At  first  the  bulla  rudiments  do  not  cause  the  mucous 
membrane  to  bulge  toward  the  lumen  of  the  nasal  cavity  and  the  early 


Frontal  furrows 


1 —   fn.fu.ndr.j) .   etTt. 


---  SvJla  eti. 


FIG.  36. — A  dissection  of  the  frontal  recess  of  a  term  fetus  showing  the  early  frontal  furrows; 
e.g.,  rudiments  of  anterior  ethmoidal  cells  and  potential  rudiments  of  the  frontal  sinus.  Particularly, 
note  the  relations  of  the  infundibulum  ethmoidale.  X  1.5. 

stages  pass  unobserved  unless  one  examines  serial  frontal  sections  through 
the  region.  Later,  however,  say  in  a  i2O-day  embryo,  the  cartilaginous 
prominences  have  developed  sufficiently  to  push  the  mucous  membrane 
on  the  lateral  wall  of  the  meatus  medius  into  relief  and  to  establish  a  fold, 
or  folds  (bullar  folds),  lateral  and  superior  to  the  processus  uncinatus.  If 
two  folds  appear  there  is  an  intervening  furrow  and  occasionally  an  eth- 
moidal cell  develops  from  it.  The  folds  represent  the  primitive  bulla 
ethmoidalis  which  usually  merge  before  or  after  birth  in  the  formation  of 
the  definitive  bulla  ethmoidalis  (Figs.  33  and  38). 

Thus  far  no  mention  has  been  made  of  another  fold  that  appears  in 
many  instances  inferior  to  the  bullar  folds  and  lateral  to  the  infundibulum 
ethmoidale.  Because  of  its  relations  to  the  infundibulum  ethmoidale  it 
is  appropriate  to  speak  of  this  as  the  infundibular  fold.  It  is  never  very 


GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 


prominent  and  forms  in  part  the  lateral  wall  of  the  infundibulum  ethmoid- 
ale.  It  may  persist  as  a  fold  after  birth,  but  it  generally  becomes  leveled 
down  to  an  even  surface  which  imperceptibly  passes  on  to  the  bullar 
surface. 

The  minor  or  accessory  conchae  or  folds  of  the  descending  ramus  of 
the  middle  meatus  may  appropriately  be  named  the  superior  and  inferior 
bullar  folds,  the  infundibular  fold  and  the  processus  uncinatus;  the  acces- 
sory furrows,  the  suprabullar  furrow  or  recess,  the  bullar  furrow,  the  infra- 
bullar  furrow,  and  the  infundibulum  ethmoidale.  The  suprabullar  recess 
and  the  infundibulum  ethmoidale  are  constant  and  important  furrows. 
The  others  are  of  little  importance  and  are  irregular  and  inconstant  in 
their  development: 


Jkcessus  frorttalis  ^~4~  ^  ~ 


Proc. 


Fronfal  furrows  of  pits 
_  .  Strive  sphenoidaHs 


Butta,   eth. 


PIG.  37. — A  dissection  of  the  frontal  recess,  etc.,  of  a  child  aged  5  months.  Note  the  pouching 
of  the  frontal  furrows  and  the  frontal  recess  in  the  formation  of  anterior  ethmoidal  cells  and  the  frontal 
sinus.  The  sphenoidal  sinus  is  also  well  established.  X  1.5. 

The  suprabullar  furrow  or  recess  is  practically  constant.  It  varies 
somewhat  in  its  form  and  extent,  but  all  specimens  give  some  evidence 
of  it.  At  times  it  continues  ventrally  and  superiorly,  almost  to  the  crib- 
riform plate  of  the  ethmoid  bone;  however,  in  the  majority  of  cases  it 
does  not  extend  so  far,  due  to  partial  fusion  between  the  superior  border 
of  the  superior  bullar  fold  and  the  attached  border  of  the  concha  media. 
It  is  frequently  also  limited  inferiorly  and  dorsally  by  similar  fusion. 
Again,  there  may  be  multiple  points  of  fusion  between  the  superior  bullar 
fold  and  the  concha  media,  thus  breaking  the  suprabullar  recess  or  furrow 
into  several  compartments  (Fig.  40).  The  recesses  in  many  cases  early 
tend  to  deepen  and  pouch  laterally  and  inferiorly  behind  the  bullar  folds. 
In  this  manner  the  bulla  becomes  more  or  less  shell-like  in  structure  and 
some  of  the  so-called  bullar  cells  established.  The  suprabullar  recess  is 
a  constant  point  from  which  anterior  ethmoidal  cells  develop. 


MINOR  NASAL  CONCHA  AND  MEATUSES  31 

The  bullar  furrow  is  placed  between  the  two  bullar  folds  or  accessory 
conchae.  It  is  variable  in  its  differentiation  and  not  at  all  constant.  It 
is  generally  obliterated  by  the  superior  and  inferior  bullar  folds  becoming 
continuous  structures  in  the  formation  of  the  adult  bulla  ethmoidalis. 
This  coalescence  is,  however,  not  always  absolute  in  that  an  ethmoidal 
cell  may  develop  from  the  furrow,  leaving  the  ostium  of  the  adult  cell  at 
the  point  of  the  primitive  furrow.  Even  in  many  adult  specimens  one 
finds  evidence  of  this  primitive  furrow  in  the  form  of  a  shallow  groove  on 
the  medial  surface  of  the  bulla  ethmoidalis.  An  ethmoidal-cell  ostium 
on  the  medial  surface  of  the  bulla  ethmoidalis  is  almost  invariably  the 
remains  of  the  early  bullar  furrow. 

The  infrabullar  furrow  is  placed  between  the  inferior  bullar  and  the 
infundibular  folds.  It  is  very  inconstant  and  not  infrequently  obliterated 


Folds  of  7>uOa  etTi. . 


FIG.  38. — The  lateral  nasal  wall  of  a  term  fetus.  The  concha  nasalis  media  is  cut  away,  thereby 
exposing  the  folds  of  the  bulla  ethmoidalis,  the  processus  uncinatus  and  the  frontal  folds  and  furrows 
for  study.  (See  text.) 

by  the  inferior  surface  of  the  bulla  ethmoidalis  becoming  continuous  with 
the  infundibular  fold.  In  some  cases  it  is  fairly  well  marked,  but  as  a 
rule  is  of  minor  importance.  Rarely  an  ethmoid  cell  develops  from  the 
furrow — the  adult  cell  draining  into  the  infundibulum  ethmoidale 
(Figs.  33  and  35). 

The  infundibulum  ethmoidale  is  invariably  present  in  some  form.  It 
is  formed  early  and  obviously  aids  in  establishing  the  primitive  processus 
uncinatus.  It  is  directed  somewhat  ventro-superiorly  and  at  its  ventral 
and  superior  termination  may  end  blindly  or  develop  into  an  anterior  eth- 
moid cell.  At  other  times  it  is  variously  continued  into  one  of  the  frontal 
furrows.  Rarely  it  continues  its  development  ventrally  and  superiorly, 
remaining  lateral  to  the  frontal  furrows  and  in  this  way  may  establish  the 


32  (;i,XKRAL  EMBRYOLOGY  AND  DEVELOPMENT 

frontal  sinus  (Figs.  36  and  127).  Dorsally  and  inferiorly  it  either  gradu- 
ally loses  its  depth  and  thus  becomes  continuous  with  the  middle  meatus, 
or  it  ends  rather  abruptly  in  a  pocket,  due  to  the  superior  and  lateral 
curving  of  the  dorsal  end  of  the  processus  uncinatus  at  this  point.  From 
the  infundibulum  ethmoidale  the  sinus  maxillaris  develops,  hence  in  the 
adult  the  latter  sinus  communicates  with  the  infundibulum  ethmoidale 
and  only  indirectly  via  the  hiatus  semilunaris  with  the  meatus  nasimedius. 
The  superior  bullar  fold  or  concha  is  located  immediately  inferior 
to  the  suprabullar  recess.  It  may  continue  independently  ventrally  and 
superiorly  almost  to  the  cribriform  plate  of  the  ethmoid  bone.  In  other 
instances  it  is  fused  at  certain  points  with  the  attached  border  of  the  concha 

Frontal  fold  or  concha 

Sv2lu  etk, 

"  ~  ~  Conc&Ji  nas.  sitprenta.il 


"  Concha,  nas.  svpronal 
Concha,  nas .  su,p.  -  - 


Concha,  nccs. 
Concha.  na& .  i,nf, 

FIG.  39. — A  frontal  recess  in  which  a  single  frontal  fold  or  concha  has  been  differentiated.  Note 
the  continuity  of  the  infundibulum  ethmoidale  with  the  furrows,  frontal  furrows,  bordering  the  fron- 
tal fold.  Compare  this  condition  with  Fig.  36.  X  1.5. 

nasalis  media.  It  is  frequently  continuous  with  one  or  more  frontal  folds. 
The  superior  bullar  fold  usually  comes  to  form  the  chief  bulk  of  the  adult 
bulla  ethmoidalis.  In  many  cases  there  is  no  differentiation  into  superior 
and  inferior  bullar  folds  by  an  intervening  furrow — the  bullar  furrow 
(Figs.  33  and  39). 

The  inferior  bullar  fold  or  concha  is,  as  stated  above,  not  always  differ- 
entiated from  the  superior  bullar  fold.  It  is,  however,  occasionally  well 
isolated  and  stands  more  or  less  as  an  independent  fold.  The  latter  con- 
dition is  especially  marked  in  the  cases  where  an  anterior  ethmoidal  cell 
develops  from  the  bullar  furrow.  The  writer  agrees  with  Killian  that  the 
superior  and  inferior  bullar  folds  (obere  und  mittlere  Nebenmuscheln, 
Killian)  usually  coalesce  to  form  the  adult  bulla  ethmoidalis.  Sometimes, 
even  in  the  adult,  one  sees  evidences  of  the  primitive  bullar  furrow  which 
more  or  less  grooves  the  medial  surface  of  the  adult  bulla.  In  manv 


MINOR  NASAL  CONCH/E  AND  MEATUSES 


33 


instances,  however,  coalescence  is  not  necessary  because  there  was  at  no 
time  a  differentiation  into  two  portions. 

The  infundibular  fold  or  concha  is  very  rudimentary  and  more  or 
less  inconstant.  It  is  located  lateral  to  the  infundibulum  ethmoidale 
and  in  part  forms  its  lateral  wall.  It  is  more  or  less  separated  from  the 
inferior  bullar  fold  by  the  shallow  infrabullar  furrow.  It  usually  loses  its 
identity  in  the  adult  in  that  it  imperceptibly  passes  to  the  bullar  surface 
by  the  obliteration  of  the  infrabullar  furrow.  Occasionally  it  is  well 
marked  and  more  or  less  isolated  from  the  inferior  bullar  fold  by  a  rela- 
tively deep  infrabullar  furrow.  Rarely  it  retains  its  identity  in  the 
adult — this  is  especially  so  when  an  anterior  ethmoidal  cell  develops 
from  the  infrabullar  furrow. 

The  processus  uncinatus  is  a  constant  structure,  and  is  medial  and 
inferior  to  the  infundibulum  ethmoidale.  As  stated  before,  it  is  the  first 
of  the  accessory  or  hidden  conchae  to  be  differentiated.  At  its  ventral 
and  superior  end  it  terminates  in  various  ways.  In  some  cases  it  is  con- 
tinuous with  one  or  more  frontal  folds  and  at  the  same  time  its  base  con- 
tinued on  to  the  agger  nasi.  In  other  instances  it  is  fused  with  the  lateral 
surface  of  the  concha  media  at  its  ventral  extremity  or  even  fused  with 
the  ventral  extremity  of  the  bulla  ethmoidalis.  Ventrally  and  inferiorly 
the  base  of  the  processus  uncinatus  becomes  continuous  with  the  surface  of 
the  agger  nasi.  Some  observers  erroneously  class  the  processus  uncinatus 
with  the  major  ethmoidal  conchae  (Figs.  22  and  25). 

2.  The  Ascending  Ramus  of  the  Meatus  Nasi  Medius  (the  recessus 
frontalis). — The  extension  of  the  middle  meatus  toward  the  frontal  region 
is  the  first  step  in  the  formation  of  the  frontal  sinus  and  certain  of  the  ante- 
rior ethmoidal  cells.  To  this  extension  or  recess  Killian1  has  given  the  appro- 
priate name,  "recessus  frontalis."  For  some  time  the  lateral  wall  of  this 
recess  (ascending  ramus  of  the  middle  meatus)  is  even  and  unbroken. 
Frontal  and  horizontal  sections  of  the  recess  of  a  4-month  fetus  reveal 
the  lateral  plate  of  cartilage  thickened  at  certain  points  in  the  form  of 
projections  directed  toward  the  lumen  of  the  nasal  fossa.  For  some  time 
this  condition  prevails  and  the  mucous  membrane  is  not  at  first  thrown 
into  relief.  These  thickenings  vary  in  number  and  are  in  anticipation  of 
the  accessory  conchae  which  are  present  on  the  lateral  wall  of  the  frontal 
recess  of  later  fetuses. 

The  frontal  folds  or  conchce  and  the  frontal  furrows  of  the  frontal  recess 
of  the  late  fetus  are  variable  in  number  and  as  a  rule  are  not  very 
prominent.  Their  prominence  depends  largely  upon  the  degree  of  devel- 

1  Anatomic  der  Nase  menschlicher  Embryonen,  Archiv  f.  Laryngolog.,  1896. 


34 


GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 


opment  of  the  intervening  furrows  or  pits  (frontal  furrows).  The  con- 
chae  or  folds  as  a  rule  more  or  less  lose  their  identity  after  birth,  and 
the  furrows  or  pits  variously  remain  as  ostia  of  anterior  ethmoidal  cells 
and  the  point  of  communication  of  the  frontal  sinus. 

As  stated  above  the  frontal  conchae  or  folds  and  furrows  vary  in 
degree  of  development  and  differentiation.  Specimens  with  four  well- 
formed  furrows  and  three  resulting  folds  are  not  uncommon.  In  other 
cases,  either  by  early  coalescence  or  lessened  differentiation,  fewer  folds 
and  furrows  are  found.  The  first  and  second  frontal  folds  or  conchas  are 
at  times  confluent  with  the  processus  uncinatus  (Fig.  36)  and  in  addition 
occasionally  extend  toward  the  agger  nasi  with  which  they  are  confluent, 


Jtecessus  frontalis  -„ 


3aZkdft...._ 


Sinus  ironfall's 


TntendM.  eth.. 
froc.  Tincinatvs 


PIG.  40. — A  dissection  from  a  child  aged  14  months  with  the  concha  nasalis  media  turned  aside. 
Apparently  no  frontal  folds  nor  furrows  were  differentiated  and  the  whole  frontal  recess  is  expanding 
toward  the  frontal  region  in  the  establishment  of  the  frontal  sinus.  Note  that  the  infundibulum 
ethmoidale  and  the  recessus  frontalis  are  discontinuous  anatomically;  moreover,  that  the  supra- 
bullar  furrow  is  represented  by  a  series  of  depressions,  rudimentary  cellulae  ethmoidales.  X  0.8. 

moreover  touch  the  lateral  surface  of  the  concha  nasalis  media  with  which 
they  fuse.  In  Fig.  35  is  represented  a  specimen  in  which  the  processus 
uncinatus. is  continued  ventrally  and  cephalically  to  the  agger  nasi,  in 
part  fusing  with  the  concha  nasalis  media  at  this  point.  The  superior 
and  inferior  bullar  folds  in  the  latter  instance  are  continued  superiorly  to 
become  continuous  with  the  first  and  second  frontal  folds.  The  third 
frontal  furrow  is  more  or  less  continuous  with  the  suprabullar  recess,  and 
the  latter  continues  almost  to  the  cribriform  plate  of  the  ethmoid  bone. 
The  infundibulum  ethmoidale  continues  ventrally  and  cephalically  into  a 
frontal  furrow.  Compare  this  condition  of  the  infundibulum  ethmoidale 
with  that  found  in  Figs.  36,  39  and  40. 

In  Fig.  39  there  is  only  one  frontal  fold  or  concha  differentiated. 


MINOR  NASAL  CONCHA  AND  MEATUSES  35 

The  concha  is  bordered  by  two  frontal  furrows,  and  the  infundibulum 
ethmoidale  is  continued  ventrally  and  superiorly  into  these  furrows. 
In  Fig.  38  the  processus  uncinatus  is  continued  ventrally  on  the  lateral 
wall  of  the  frontal  recess  and  apparently  the  frontal  folds  extend  from  it. 
At  times  the  frontal  folds  or  conchae  fuse  with  the  lateral  surface  of  the 
concha  nasalis  media  and  obliterate  the  frontal  recess  as  such.  In  these 
cases  the  sinus  frontalis  must  develop  from  an  anterior  ethmoidal  cell, 
and  not  by  direct  extension  of  the  frontal  recess  (Fig.  150).  In  Fig.  147 
the  frontal  folds  have  not  fused  with  the  lateral  surface  of  the  concha 
nasalis  media,  the  frontal  recess  being  maintained.  In  such  a  condition 
the  sinus  frontalis  may  develop  either  from  the  frontal  recess  or  from  one 
or  more  anterior  ethmoidal  cells.  It  is  difficult  to  say  in  the  latter  dissec- 
tion whether  the  frontal  folds  or  conchae  have  coalesced  with  one  another, 
thus  constricting  off  small  blind  pouches  (early  anterior  ethmoidal  cells), 
or  whether  the  frontal  furrows  in  anticipation  of  anterior  ethmoidal  cells 
have  pouched  toward  the  frontal  region,  thus  closely  simulating  coales- 
cence between  the  several  frontal  folds,  but  making  coalescence  apparent 
rather  than  real. 

(3)  The  Descending  Ramus  of  the  Meatus  Nasi  Superior. — At  this 
juncture  mention  must  again  be  made  of  a  frequent  accessory  concha 
differentiated  rather  early  and  well  established  by  the  fourth  month  of 
fetal  life  on  the  lateral  wall  of  the  descending  ramus  of  the  meatus  nasi 
superior.  In  specimens  where  the  accessory  concha  of  the  superior  meatus 
is  well  developed,  fairly  well  formed  superior  and  inferior  recesses  are 
established  on  the  lateral  meatal  wall.  The  inferior  recess  is  especially 
deep  in  the  cases  where  the  "crista  suprema"  of  Killian  is  well  developed. 
This  condition  makes  the  superior  meatus  look  much  like  the  middle 
meatus,  i.e.,  the  accessory  concha  of  the  superior  meatus  takes  the  place 
of  the  bulla  ethmoidalis  (accessory  concha  of  the  middle  meatus),  and 
the  "crista  suprema"  takes  the  place  of  the  processus  uncinatus  (compare 
Figs.  21  and  34). 

The  inferior  recess  of  the  superior  meatus  may  continue  ventro- 
cephalically  into  the  blind  superior  termination  of  the  superior  meatus. 
The  accessory  concha  is,  however,  at  times  wholly  or  in  part  coalesced 
with  the  concha  media,  thus  obliterating  wholly  or  partly  the  inferior  recess. 
Frequently  a  posterior  ethmoidal  cell  develops  from  the  inferior  recess. 
The  superior  recess  is  often  obliterated  by  coalescence  between  the  acces- 
sory concha  and  the  concha  superior.  In  other  instances  the  superior 
recess  too  is  continued  ventrocephalically  to  the  blind  end  of  the  meatus 
superior.  Occasionally  an  ethmoidal  cell  develops  from  this  recess. 


36  (IKXKRAL  KM  BRYOLOGY  AND  DEVELOPMENT 

(C)  The  Rudiments  or  Anlages  of  the  Paranasal  (Accessory)  Sinuses. 
—The  paranasal  sinuses  are  preformed  in  the  major  and  minor  nasal 
meatuses  (none  develop  from  the  meatus  nasi  inferior).  This  is  true  for 
all  the  paranasal  sinuses  save  the  sphenoidal  which  arises  in  connection 
with  the  posterior  cupola  of  the  cartilaginous  nasal  capsule,  and  in  a  sense 
is  primarily  a  constriction  of  the  nasal  mucosa  from  the  dorsocephalic 
part  of  the  nasal  fossa. 

After  the  preceding  consideration  of  the  nasal  meatuses  and  concha? 
and  the  accessory  conchse  and  furrows,  the  genesis  of  the  paranasal  sinuses 
becomes  much  simplified  and  fairly  easy  of  interpretation.  Since  the 
paranasal  or  accessory  sinuses  develop  from  preformed  furrows  and  re- 
cesses, it  is  difficult  to  say  just  when  they  have  established  rudiments. 
The  author  believes,  however,  that  rudiments  are  established  much  earlier 
than  is  generally  supposed.  Indeed,  the  furrows  and  recesses  from  which 
the  paranasal  sinuses  develop  are,  in  a  sense,  the  "primitive"  rudiments 
of  these  chambers.  The  early  tendency  for  the  sinuses  to  establish  their 
''first"  rudiments  may  be  no  mean  factor  in  making  the  recesses  and 
furrows  what  they  early  are. 

The  pre-existing  spaces  from  which  paranasal  air  chambers  develop, 
according  to  the  writer's  specimens  and  studies,  are:  (i)  the  suprabullar 
recess,  (2)  the  bullar  furrow,  (3)  the  infrabullar  furrow,  (4)  the  infundi- 
bulum  ethmoidale,  all  of  the  descending  ramus  of  the  meatus  nasi  medius ; 
(5)  the  frontal  furrows,  (6)  the  frontal  recess,  both  of  the  ascending  ramus 
of  the  meatus  nasi  medius;  (7)  the  ventral  and  superior  extremity  of  the 
meatus  nasi  superior,  (8)  the  recessus  superior,  (9)  the  recessus  inferior,  all 
of  the  meatus  nasi  superior;  (10)  the  meatus  nasi  supremus  I.  Of  the 
foregoing  named  spaces,  paranasal  sinuses  or  cells  rarely  develop  from  the 
infrabullar  furrow  and  only  occasionally  from  the  bullar  furrow.  Poste- 
rior ethmoidal  cells  develop  rather  frequently  from  the  inferior  and  superior 
recesses  of  the  meatus  nasi  superior,  and  in  about  75  per  cent,  of  speci- 
mens in  which  the  meatus  supremus  I  persists,  a  posterior  ethmoidal  cell 
develops  from  it  (the  meatus  nasi  supremus  I  is  present  in  about  62  per 
cent,  of  adult  specimens).  The  remainder  of  the  aforementioned  spaces 
are  practically  constant  in  the  development  of  paranasal  sinuses  or  cells. 

The  paranasal  sinuses  as  such  are  primarily  evaginations  of  the  nasal 
mucous  membrane  in  fairly  definite  regions  of  the  nasal  meatuses  men- 
tioned. These  early  evaginating  sacs  wander  into  neighboring  portions  of 
the  nasal  walls  by  a  joint  growth  of  the  sacs  and  an  absorption  of  bone, 
until  goodly  portions  of  the  ethmoid,  frontal,  maxillary  and  sphenoid  bones 
are  pneumatized  in  the  formation  of  the  cellulae  ethmoidales,  the  sinus  f ron- 


DEFINITIVE  NASAL  SEPTUM  37 

tails,  the  sinus  maxillaris,  and  the  sinus  sphenoidalis,  respectively.  The 
conchal  cells  are,  of  course,  outlying  ethmoidal  cells  and  in  their  origin 
and  development  are  in  all  respects  in  agreement  with  the  ethmoidal  cells 
proper.  In  some  cases,  particularly  the  ethmoidal  cells,  ossification  of 
the  cartilaginous  walls  of  the  mucous  membrane  sacs  takes  place  around 
the  cells,  the  point  of  original  outgrowth  remaining  as  the  permanent 
ostium  of  the  respective  cell.  Indeed,  no  matter  how  far  a  cell  or  sinus 
may  grow  into  a  neighboring  bone,  its  initial  point  of  outgrowth  from  the 
nasal  fossa  persists  in  the  adult  as  the  ostium  of  the  cell  or  sinus. 

In  subsequent  paragraphs  each  paranasal  sinus  and  groups  of  cells 
will  be  discussed  under  three  heads:  (i)  the  fetal  stage,  (2)  the  childhood 
stage,  and  (3)  the  adult  stage.  In  order  that  there  may  be  no  unnecessary 
repetition  a  further  consideration  of  the  early  anatomy  of  the  paranasal 
sinuses  as  exhibited  in  the  fetus  will  be  deferred  for  discussion  in  connection 
with  the  sinus  concerned. 

THE  DEFINITIVE  NASAL  SEPTUM 

The  median  frontonasal  process,  one  of  the  "trabeculae  cranii,"  is 
early  divided  into  two  lateral  processes  (lateral  nasal  processes)  and  two 


PIG.  41. — The  nasal  septum  of  a  child  aged  18  months.     Particularly  note  the  septal  plicae  (plicae 

septi)   and  the  sinus  sphenoidalis.       X  0.7. 

Ps.   =  plicae  septi;  Tp.   =  tonsilla  pharyngea;  Ss.   =  sinus  sphenoidalis;  Cs.   =  concha  sphenoidalis; 
He.    =  hypophysis  cerebri. 

mesial  processes  (mesial  nasal  processes).  These  form  the  walls  of  the 
primitive  nasal  fossae.  The  mesial  nasal  processes  fuse  in  the  formation  of 
the  central  portion  of  the  upper  lip,  the  premaxillary  process  (not  to  be 
confused  with  a  premaxillary  bone),  and  the  primary  nasal  septum.  Sub- 
sequently, as  stated  elsewhere,  and  coincidently  with  other  changes, 
the  primary  nasal  septum  grows  dorsally  toward  the  pharynx  and  caudally 
toward  the  mouth  in  the  formation  of  -the  secondary  nasal  septum, 


38  GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 

ultimately  fusing  with  the  nasal  surface  of  the  palate  and  forming  a 
free  border  dorsally  between  the  definitive  choanae  or  posterior  nares. 
It  is,  therefore,  obvious  that  the  definitive  or  final  nasal  septum  is  made  up 
of  primary  and  secondary  portions,  both  derivatives  of  the  mesial  part 
of  the  frontonasal  process. 

The  primary  nasal  septum  is  at  first  thick,  separating  widely  the 
early  olfactory  fossae,  the  secondary  septum  -relatively  thin.  The 
definitive  nasal  septum  gradually  becomes  thinner  and  thinner,  the 
nares  coming  to  occupy  positions  nearer  the  mid-plane,  and  a  laminar 
plate  of  cartilage  develops  in  its  substance.  A  fairly  heavy  mucous 
membrane  covers  both  surfaces  of  the  septum,  part  of  which  forms  a  paired 
tubular  organ  in  the  ventrocaudal  portion  of  the  septum  immediately 
dorsal  and  cephalic  to  the  incisive  foramen  (the  >vomeronasal  organ). 
The  glands  of  the  nasal  mucosa  develop  as  solid  processes  during  the  third 
and  fourth  months,  but  do  not  reach  their  complete  development  until 
after  birth.  Moreover,  the  mucous  membrane  of  the  nasal  septum  of  the 
fetus  usually  presents  well-developed  folds  in  the  region  of  the  later 
vomer  (septal  folds,  plicae  septi).  The  author  has  frequently  noticed  a 
preponderance  of  epithelial  thickness  in  this  region  of  the  septum  as 
early  as  the  third  month  of  uterine  life.  The  septal  folds  and  inter- 
vening furrows  increase  in  size  until  the  seventh  or  eighth  month,  then 
undergo  a  retrograde  metamorphosis.  They  usually  disappear  in  early 
infancy.  However,  the  septal  plicae  may  persist,  even  hypertrophy  and 
form  tumor-like  obstructing  masses  in  the  adult  (Fig.  41). 

Portions  of  the  laminar  plate  of  cartilage  remain  and  form  the  septal 
cartilage  and  the  vomerine  cartilages,  and  other  parts  are  replaced  by  bone. 
It  is,  therefore,  obvious  that  the  nasal  septum  passes  through  three  distinct 
stages:  (i)  the  membranous,  (2)  the  cartilaginous,  and  (3)  the  adult 
mixed  cartilaginous  and  osseous  (see  pages  78  and  81). 

THE  DEVELOPMENT  OF  THE  NASAL  SKELETON 

(A)  The  Cartilaginous  Nasal  Capsule. — The  nasal  capsule  and  the 
ethmoidal  region  are  the  last  portions  of  the  chondrocranium  to  become 
cartilaginous  (Fig.  42).  Generally  speaking,  the  nasal  capsule  and  the 
ethmoidal  region  are  membranous  as  late  as  the  eighth  month  of  em- 
bryonal life  (20  mm.  embryos);  however,  the  lateral  wall  of  the  nasal 
capsule  and  the  nasal  septum  are  obviously  in  the  precartilage  stage  as 
evidenced  by  mesenchymal  condensation.  By  the  middle  of  the  third 
month  of  embryonal  life  the  nasal  capsule  is  well  advanced  as  a  cartilagi- 


CARTILAGINOUS  NASAL  CAPSULE 


39 


nous  structure.  Cartilage  extends  into  the  nasal  septum  from  the  body 
of  the  sphenoid.  The  lateral  walls  of  the  nasal  cavity  chondrify  inde- 
pendently, later  joining  the  nasal  septum  ventrally  to  form  the  cartilagi- 
nous roof  and  lateral  walls  of  the  nasal  cavity.  Subsequently,  the  lateral 
cartilaginous  walls  connect  up  dorsally  where  the  sphenoidal  and  septal 
cartilages  are  confluent.  The  inferior  margin  of  the  lateral  cartilage 
infolds  behind  the  naris  and  becomes  the  cartilage  of  the  maxillo  (inferior)  - 
turbinate.  This  infolding,  at  first  simple,  becomes  more  complex  by  the 
formation  of  accessory  processes  and  folds.  During  the  seventh  month 


FIG.  42. — The  cartilaginous  nasal  capsule  from  a  human  fetus  aged  4  months.     (Adapted  from 

Kollmann.) 
fo   =  foramen  opticum;  C.   nasalis   =  capsula  nasalis;  lac,    =  lacrimal. 

it  becomes  separated  from  the  lateral  wall.  In  the  adult  the  maxillo 
(inferior)  turbinate  (concha  nasalis  inferior)  is  an  independent  bone. 

The  early  membranous  conchal  (turbinal)  folds,  comprised  of  epithe- 
lium and  underlying  mesenchyme,  develop  cores  of  precartilage  (condensed 
mesenchyme).  The  condensed  mesenchymal  cores  chondrify  during  the 
fourth  month  of  embryonal  life.  As  stated  before,  the  initial  conchal  or 
turbinal  folds  are  not  due  to  an  inpushing  of  the  mucosa  by  the  cartilag- 
inous strands,  e.g.,  cartilage  develops  within  the  folds,  but  does  not  grow 
into  them  (see  page  19  and  Figs.  14  and  15). 

During  the  third  month  of  fetal  life  a  short,  stumpy  cartilaginous 
process  (processus  paranasalis)  arises  from  the  lateral  wall  of  the  carti- 
laginous nasal  capsule  to  surround  the  developing  nasolacrimal  duct. 


40  GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 

The  fate  of  the  several  portions  of  the  cartilaginous  nasal  capsule 
varies.  Certain  parts  persist  and  are  carried  over  as  cartilage  into  the 
skeleton  of  the  adult  nose  (the  cartilaginous  portion  of  the  septum  and 
the  cartilages  of  the  external  nose) ;  others  become  ossified  as  individual 
bones  to  participate  in  the  formation  of  the  adult  nasal  skeleton  (the 
ethmoid  bone,  including  the  ethmoturbinals,  the  maxilloturbinal,  and  the 
sphenoturbinal) ;  and,  thirdly,  some  portions  are  soon  overlaid  by  connect- 
ive tissue  osseous  rudiments  or  anlages  and  the  cartilage  for  the  most  part 
absorbed.  For  example,  parts  of  the  septum  and  of  the  lateral  wall  above 
the  maxilloturbinal  disappear  and  are  replaced  by  parts  of  the  neighboring 
membrane  bones.  Moreover,  the  original  continuity  of  the  cartilaginous 
nasal  capsule  is  broken  by  division  into  smaller  portions  brought  about  by 
the  ingrowth  of  connective  tissue  at  various  points.  ,This  leads  during  the 
sixth  month  to  the  formation  of  the  individual  alar  cartilages  and  the 
detachment  of  the  cartilaginous  nasal  septum  from  the  anterior  portion 
of  the  lateral  cartilage.  Posteriorly  the  connections  with  the  lateral 
cartilage  are  retained. 

(B)  Ossification  of  the  Elements  that  Participate  in  the  Boundaries 
of  the  Cavum  Nasi. — In  this  connection  it  will  be  necessary  to  consider 
parts  that  arise  in  relation  with  the  cartilaginous  nasal  capsule  and  others 
which  from  a  developmental  standpoint  are  not  related. 

i.  The  Ethmoid  Bone  (os  ethmoidale). — The  greater  portion  of  the  pos- 
terior part  of  the  cartilaginous  nasal  capsule  becomes  the  ethmoid  bone. 
The  lateral  and  one  medial  primary  and  several  secondary  ossification 
centers  appear  in  the  capsule.  Each  lateral  center  appears  in  the  fifth 
or  sixth  fetal  month  and  gives  rise  to  an  orbital  plate  (os  planum, 
lamina  papyracea),  ossification  extending  into  the  lamina  cribrosa  and 
into  the  ethmoturbinals  during  the  seventh  and  eighth  months.  In  this 
manner  permanent  osseous  foramina  are  formed  for  the  olfactory  nerves 
and  the  mucosa-walled  ethmoidal  air  cells  gain  bony  boundaries.  During 
the  first  year  of  postfetal  life  ossification  begins  in  the  cephalic  portion 
of  the  cartilaginous  nasal  septum  to  form  the  lamina  perpendicularis  of 
the  ethmoid  and  extends  into  the  crista  galli  and  the  cribriform  plate. 
Secondary  centers  appear  later.  The  date  of  the  bilateral  union  of  the 
three  pieces  (lamina  cribrosa,  lamina  perpendicularis  and  lamina  papy- 
racea) is  uncertain.  A  study  of  a  few  specimens  would  indicate  that  the 
fusion  takes  place  late  in  the  sixth  year.  The  ethmoidal  cells  are  primarily 
evaginations  of  the  nasal  mucosa  which  grow  into  the  lateral  ethmoidal 
masses  and  their  appendages  (the  ethmoturbinalia)  and  by  further  growth 
of  the  sacs  and  the  absorption  of  bone  become  well  established  as  the  cellu- 


OSSIFICATION  OF  NASAL  CAPSULE  41 

lar  ethmoidal  labyrinth.  The  ossification  of  the  ethmoid  is  not  com- 
pleted until  the  end  of  the  seventeenth  year.  The  lamina  perpendicu- 
laris  ultimately  (45  to  50  years)  unites  with  the  vomer.  The  posterior 
dome  or  cupola  of  the  cartilaginous  nasal  capsule  in  man  ossifies  as  the 
sphenoidal  turbinate  or  concha  (ossiculum  Bertini). 


FIG.  43. — A  photograph  indicating  stage  of  development  of  the  osseous  elements  of  the  head  in  a 

fetus  at  term.      X  0.45.     (Courtesy  of  Mutter  Museum,  College  of  Physicians.) 

a  =  occipital;  b  =  parietal;  c  =  sphenoid;  d  —  vomer;  e  =  ethmoid;  /  =  palate;  g  =  nasal; 
h  =  inferior  turbinate;  *  =  lacrimal;  k  =  maxilla;  /  =  frontal;  m  =  temporal;  n  =  zygomatic; 
o  =  dentes;  p  =  mandible;  r  —  ear  ossicles. 

2.  The  Vomer. — The  true  vomer  develops  bilaterally  on  each  side 
of  the  caudal  and  dorsal  portion  of  the  cartilaginous  nasal  septum  from  a 
pair  of  ossification  centers  during  the  eighth  week  of  fetal  life.  This  is  in 
agreement  with  Mall.  These  centers  unite  beneath  the  caudal  border  of 
the  septal  cartilage,  but  grow  cephalically  on  each  side  of  the  septum  as 
two  plates,  thus  enclosing  the  cartilage.  The  bilateral  plates  of  the  vomer 
unite  from  behind  forward  at  the  expense  of  the  imprisoned  cartilage, 
union  being  completed  by  the  fifteenth  year.  The  vomer  of  the  young 
infant  shows  clearly  its  formation  in  two  plates  (Fig.  43).  In  the  adult, 


42  GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 

on  the  other  hand,  the  bilaterality  of  the  vomer  is  indicated  merely  by 
the  groove  between  the  alae  and  by  the  groove  on  the  lower  part  of  the 
ventral  border  where  it  receives  the  triangular  septal  nasal  cartilage. 
In  spite  of  the  fact  that  the  vomer  develops  on  each  side  of  the  cartilag- 
inous nasal  septum  and  at  its  expense,  it  must  be  classed  as  a  true  membrane 
bone.  Rarely  a  patch  of  cartilage  persists  between  the  bilaminar  vomer 
and  develops  into  a  chondroma  subsequently. 

3.  The  Maxilloturbinal  (concha  nasalis  inferior). — The  inferior  nasal 
concha  or  turbinal  arises  in  cartilage  from  the  lower  inturned  border  of 
the  lateral  plate  of  the  cartilaginous  nasal  capsule.     It  develops  from  a 
separate  ossific  center  which  appears  about  the  middle  of  fetal  life. 

4.  The  Palate  Bone   (os  palatinum). — The  palate  is  a  membrane 
bone  arising  according  to  recent  studies  from  a  single  ossification  center 
located  at  the  junction  of  the  horizontal  and  vertical  portions  of  the  bone 
(Mall1  and  Fawcett2).     The  ossific  center  appears  at  the  end  of  the  second 
month  of  fetal  life.     The  vertical  portion  of  the  palate  bone  extends 
upward  on   the  medial  surface  of  the  lateral  wall  of  the  cartilaginous 
nasal  capsule;  the  latter  intervening,  therefore,  between  the  palate  bone 
and   the   maxilla.     At   a   subsequent   period   the   intervening   cartilage 
undergoes  resorption.     The  horizontal  part  ossifies  in  the  dorsal  portion 
of  the  definitive  palate  which  it  helps  to  form. 

5.  The  Nasal  Bone  (os  nasale). — The  nasal  bone  is  bilaterally  present 
and  develops  in  membrane  on  the  surface  of  the  cartilaginous  nasal 
capsule.     The  subjacent  cartilage  can  be  demonstrated  as  late  as  the  first 
month  of  postfetal  life,  then  becomes  absorbed.     It  is  generally  believed 
that   the   bone   develops   from   a   single   ossific  center.     Perna  (i9o6)3 
believes  that  the  nasal  bone  develops  from  two  rudiments,  a  lateral  mem- 
branous and  a  small  median  cartilaginous.     A  small  Wormian  bone  may 
develop  in  the  median  line  between  the  nasals  and  the  frontal.     Ape-like 
the  two  nasals  sometimes  coossify.     Bilateral  and  unilateral  absence  of 
the  nasal  bone  occurs  (see  page  65  for  a  consideration  of  the  variations 
of  the  nasal  bones). 

6.  The  Lacrimal  Bone  (os  lacrimale). — The  lacrimal  bone  arises  in 
membrane  on  the  lateral  wall  of  the  cartilaginous  nasal  capsule.     It 
ossifies  from  one  or  more  centers  which  appear  during  the  third  month 
of  fetal  life.     The  adult  bone  is  occasionally  divided.     According  to  Mall 

1  On  centers  of  ossification  in  human  embryos  less  than  100  days  old,  Amer.  Jour.  Anat,  Vol.  5, 
1896. 

2  On  the  development,  ossification,  and  growth  of  the  palate  bone  of  man,     Jour,  of  Anat.  and 
Physiol.,  Vol.  40,  1906. 

*  Die  Nasenbeine,  Arch.  f.  Anat.  u.  Physiol.  Anat.  Abt.,  1006. 


OSSIFICATION  OF  NASAL  CAPSULE  43 

the  bone   ossifies  from   one   center  which  appears  on  the  eighty-third 
day. 

7.  The  Sphenoid  Bone  (os  sphenoidale).— The  sphenoid  bone  is 
in  part  preformed  in  cartilage  and  in  part  in  membrane.  Ten  principal 
centers  of  ossification  arise  in  the  cartilage  that  corresponds  to  this  bone, 
one  for  each  great  wing  during  the  eighth  week  of  fetal  life  (alisphenoid), 
one  for  each  small  wing  (orbitosphenoid),  two  for  the  body  between  the 
great  wings  during  the  early  part  of  the  third  month  of  fetal  life  (basi- 
sphenoid),  two  for  the  body  between  the  small  wings  during  the  second 
month  (presphenoid),  and  one  for  each  lingula  during  the  fourth 
month. 

Membrane  bone  forms  the  orbital  and  temporal  portions  of  the  great 
wings  and  the  medial  laminae  of  the  pterygoid  processes  (the  hamular 
processes  excepted). 

The  presphenoid  and  the  lesser  wings  unite  before  birth.  About 
the  eighth  month  of  fetal  life  the  pre-  and  basisphenoids  unite,  but  at 
birth  and  for  sometime  longer  these  parts  are  still  separated  by  cartilage 
on  their  inferior  surfaces.  During  the  first  year  of  postfetal  life  the  several 
parts  of  the  sphenoid  coalesce. 

The  sphenoturbinals  in  the  adult  are  fused  to  the  ventral  surface  of 
the  body  of  the  sphenoid  bone  and  form  the  ventral  boundaries  of  the 
paired  sphenoidal  sinuses.  Developmentally,  however,  these  turbinals 
are  separate  and  individual  bones  and  merit  further  discussion.  The 
embryology  and  anatomy  of  the  sphenoidal  sinuses  will  foe  discussed  in 
other  paragraphs  (see  Chapter  V). 

8.  The  Sphenoturbinal  (concha  nasalis  sphenoidalis,  ossiculum 
Bertini). — The  sphenoturbinal  bone  js  a  bilateral,  thin,  cap-like  plate 
which  appears  before  birth  at  the  front  of  the  presphenoid.  It  develops 
as  an  independent  element  from  ossjfic  centers  associated  with  the 
posterior  cupola  of  the  cartilaginous-liasal  capsule  during  the  latter  half 
of  fetal  life.  The  centers  appear  in  the  medial  and  lateral  walls  of  the 
cupola,  later  to  be  connected  by  secondary  ossific  centers  in  the  mem- 
branous portion  of  the  cupola  toward  the  termination  of  fetal  life.  "At 
the  time  of  the  third  year  the  cupola-shaped  recess  or  terminal  nasal  sinus 
(the  early  sphenoid  sinus)  is  surrounded  by  bone  and  lined  with  nasal 
mucosa,  except  toward  the  nasal  fossa,  where  an  opening  or  ostium 
persists  (the  primary  ostium  sphenoidale  or  opening  into  the  sphenoidal 
sinus) .  The  sphenoturbinals  cover  the  ventral  and  caudal  surfaces  of  the 
presphenoid  and  at  five  years  are  still  free  from  the  sphenoid  bone, 
membranous  tissue  intervening  (Fig.  132).  During  the  fourth  year, 


44 


GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 


however,  the  cephalic  and  medial  parts  of  the  nasal  capsule  begin  to  be 
absorbed  and  then  the  presphenoid  participates  in  bounding  the  terminal 
nasal  sinus,  e.g.,  the  sinus  sphenoidalis.  This  gives  the  sphenoidal  sinus 
an  opportunity  to  grow  into  the  body  of  the  sphenoid  bone,  and  the 
sphenoturbinals  instead  of  presenting  rounded  openings  in  the  disar- 
ticulated bone  present  notches.  The  persistent  portions  of  the  spheno- 
turbinals unite  first  (fifth  year)  with  the  ethmoid  and  ultimately  (ninth 
to  twelfth  year)  with  the  sphenoid  and  palate  bones.  Their  identity 
and  individuality  is  from  then  on  lost. 

9.  The  Maxilla. — Cartilage  fails  to  appear  in  the  maxillary  process 
of  the  first  branchial  arch  due  probably  to  the  rapid  development  of  the 
parts  concerned,  wherefore  the  palate  bone  and  the  maxilla  arise  directly 
in  membrane.  Ossification  of  the  maxilla  commences  in  the  sixth  or 
seventh  week  of  embryonal  life  as  one  center  (Hertwig,  Mall,  Schaeffer) 
from  which  an  ossifying  process  soon  extends  toward  the  frontal  bone  in 
the  formation  of  the  frontal  process  of  the  maxilla.  Later  extensions 
from  the  primary  ossific  center  develop  into  the  orbital,  alveolar,  and 
palatine  processes.  Moreover,  a  single  ossific  center  appears  in  the  related 
half  of  the  intermaxillary  mass  which  establishes  union  with  the  center 
in  the  maxilla  proper  early  in  the  third  month  of  fetal  life.  Albrecht 
erroneously  believed  that  each  premaxilla  was  made  up  of  two  bones. 
According  to  Mall  both  the  centers  of  the  premaxilla  and  the  maxilla  par- 
ticipate in  the  formation  of  the  frontal  process. 

Initially,  the  maxilla  lies  ectal  to  the  cartilaginous  nasal  capsule. 
Subsequent  absorption  of  a  goodly  portion  of  the  nasal  capsule  allows  the 
maxilla  to  participate  in  forming  the  lateral  nasal  walls,  to  complete  the 
osseous  boundaries  of  certain  ethmoidal  cells,  to  articulate  with  the  maxil- 
loturbinal,  and  to  become  the  bone  for  the  reception  and  development  of 
an  evaginating  nasal-mucous-membrane  pouch  destined  to  become  the 
sinus  maxillaris  (antrum  of  Highmore).  The  formation  of  the  alveolar 
process  begins  as  early  as  the  fourth  fetal  month,  but  is  not  completed 
until  the  twenty-fourth  year. 

It  will  be  recalled  that  in  the  third  or  fourth  month  a  stumpy  cartilag- 
inous process  (processus  paranasalis)  arises  from  the  lateral  wall  of  the 
cartilaginous  nasal  -capsule  and  surrounds  the  developing  nasolacrimal 
duct.  Apropos  of  this,  one  frequently  finds  cartilaginous  masses  in  the 
alveolar  part  of  the  developing  maxilla  which  have  no  connection  with 
the  nasal  capsule.  Mihalkovics  suggests  (1899)  that  these  masses  of 
cartilage  are  portions  of  the  processus  paranasalis  caught  in  the  ossifying 
maxilla.  The  masses  usually  disappear. 


OSSIFICATION  OF  NASAL  CAPSULE  45 

The  infraorbital  vessels  and  nerve  occupy  for  some  time  a  mere  groove 
on  the  orbital  surface  of  the  maxilla,  later  to  become  encased  by  an  in- 
growth over  them  of  a  lamina  of  bone.  At  times  the  osseous  floor  of  the 
infraorbital  canal  remains  deficient  and  the  nerve  and  vessels  are  then 
separated  from  the  cavity  of  the  maxillary  sinus  merely  by  the  mucous 
membrane.  The  sinus  maxillaris  in  its  relations  to  the  maxilla  and  to 
the  deciduous  and  permanent  teeth  will  be  discussed  subsequently  (see 
Chapter  III). 

10.  The  Frontal  Bone  (os  frontale). — The  frontal  bone  participates 
to  a  limited  degree  in  bounding  the  nasal  cavity  and  is  the  bone  of  recep- 
tion for  the  evaginating  mucous-membrane  sac  or  sacs  from  the  frontal 
recess  of  the  middle  nasal  meatus  to  become  topographically  the  frontal 
sinus  or  sinuses. 

The  bone  is  developed  in  membrane.  According  to  the  studies  of 
Mall,1  in  which  the  writer  concurs,  in  the  region  of  the  future  frontal 
eminences  appear  during  the  eighth  week  two  major  ossific  centers. 
Additional  centers  at  times  appear.  At  birth  the  frontal  bone  is  divided 
into  right  and  left  halves  which  become  approximated  during  the  first 
year  and  fuse  along  the  metopic  suture  during  the  second  year.  This 
fusion  may  be  delayed  until  the  seventh  or  ninth  year  or  may  never  take 
place.  The  metopic  suture  may  persist  throughout  or  may  be  retained 
at  its  lower  extremity;  then  forming  a  metopic  fontanelle.  Wormian 
bones  (ossa  metopica)  may  develop  in  the  region  of  the  metopic  fontanelle 
during  the  process  of  ossification.  Metopic  ossicles  may  develop  in  other 
parts  of  a  persistent  metopic  suture. 

The  frontal  sinus  begins  to  develop  during  the  fourth  or  fifth  month 
of  fetal  life  in  the  region  of  the  frontal  recess  of  the  middle  nasal  meatus, 
but  is  not  topographically  frontal  until  some  time  after  birth.  It  develops 
slowly  until  the  seventh  or  eighth  year,  then  more  rapidly  up  to  the 
twentieth  year  and  increases  somewhat  in  size  up  to  old  age.  A  persist- 
ent metopic  suture  precludes  the  development  of  a  frontal  sinus  beyond 
the  mid-sagittal  plane;  at  least  this  is  true  in  all  such  skulls  observed  by 
the  writer  (Fig.  66). 

(C)  Skeleton  Changes  Incident  to  Growth. — At  birth  the  facial 
skeleton  is  relatively  small  due  in  part  to  the  small  size  of  the  nasal  fossae 
and  maxillary  sinuses.  The  nasal  fossae  are  as  wide  as  they  are  high.  The 
bony  nasal  aperture  is  relatively  broad  and  its  caudal  border  but  little 
below  the  plane  of  the  orbit.  Moreover,  the  nasal  aperture  and  cavity 
are  not  clearly  separated  from  the  face.  The  bony  choanae  (posterior 


46  GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 

nares)  are  relatively  small,  5  to  7  mm.  in  the  vertical  diameter  and  7  to 
8  mm.  in  the  transverse  (coronal).  By  the  sixth  month  of  extrauterine 
life  the  choanal  diameters  have  doubled;  however,  the  diameters  remain 
such  as  to  give  more  or  less  circular  choanae.  After  puberty  the  vertical 
diameter  is  always  greater  than  the  transverse  and  the  shape  of  the  cho- 
anae is  changed  from  circular  to  oblong.  This  change  in  the  diameters  of 
the  choanae  is  due  to  unequal  growth :  At  birth  the  dorsal  border  of  the 
hard  palate  is  on  a  plane  with  the  occipito-sphenoidal  articulation ;  during 
the  third  year  it  drops  to  the  mid-plane  of  the  basi-occipital,  and  by  the 
sixth  year  is  essentially  in  the  adult  plane,  e.g.,  the  ventral  border  of  the 
foramen  magnum. 

It  will  be  recalled  that  the  maxillary  turbinal  field  of  the  early  nasal 
fossa  occupies  almost  the  entire  lateral  wall  (Fig.  1 7) .  Later  the  ethmoidal 
turbinal  field  begins  to  be  formed  and  soon  outdistances  the  maxillary  in 
the  extent  of  its  vertical  plane.  Indeed,  at  birth,  as  shown  by  Kallius,  the 
ethmoidal  part  of  the  nasal  fossa  is  twice  the  height  of  the  maxillary  in 
spite  of  the  fact  that  in  the  adult  the  two  portions  are  equal.  This  means 
that  the  maxillary  portion  grows  faster  after  birth,  catching  up  approxi- 
mately the  seventh  year  when  the  adult  relations  are  attained.  Dentition 
and  the  development  of  the  maxillary  sinus  may  have  some  bearing  on  this 
relationship.  The  inferior  meatus  remains  very  narrow  until  after  the 
deciduous  teeth  have  erupted.  Before  this,  owing  to  a  relatively  large 
inferior  concha,  there  is  little  room  in  the  inferior  meatus  for  the  passage 
of  air — the  concha  almost  touching  the  floor  of  the  nose  (see  maxillary 
sinus,  page  107). 

The  skull  at  birth  shows  a  relatively  large  cranial  portion  and  a 
small  facial  when  compared  with  the  skull  of  the  adult.  Froriep  estimated 
the  ratios  to  be  8  :  i  in  a  "term"  child,  4  :  i  at  five  years  of  age,  and  2  :  i  in 
the  adult.  At  birth  the  vertical  diameters  of  the  maxillae  and  the  nasal 
fossae  are  small.  Added  to  these  the  alveolar  processes,  owing  to  the 
rudimentary  condition  of  the  teeth,  are  likewise  small.  It  is  frequently 
stated  that  the  increase  of  the  facial  diameters  after  birth  is  in  a  measure 
due  to  the  pneumatization  of  the  maxillae,  ethmoid,  sphenoid  and  frontal 
bones  by  the  related  paranasal  sinuses.  While  it  is  true  that  facial  in- 
crease is  associated  with  the  development  of  the  nasal  sinuses,  the  writer 
is  strongly  of  the  opinion  that  it  is  erroneous  to  think  of  the  paranasal 
sinuses  as  forcing  the  face  parts  to  develop  or  that  the  development  of 
the  sinuses  is  delayed  until  other  parts  have  grown  sufficiently  to  permit 
of  their  expansion.  The  writer  believes  that  developmental  processes 
go  on  hand  in  hand  and  that  when  a  certain  time  is  reached  a  structure 


EPITHELIUM  OF  PRIMITIVE  NASAL  FOSSAE  47 

will   normally  have   attained  proportions  for  that  period   regardless  of 
related  parts. 

THE  EPITHELIUM  OF  THE  PRIMITIVE  NASAL  FOSS.E 

The  Olfactory  Nerves. — During  the  third  or  fourth  week  of  em- 
bryonic life  the  lining  of  the  primitive  nasal  fossae  undergoes  histogenic 
changes;  indeed,  not  unlike  those  seen  in  the  wall  of  the  neural  tube. 
The  undifferentiated  epithelium  invaginated  from  the  surface  in  the  forma- 
tion of  the  olfactory  fossae  undergoes  proliferation  and  in  addition  to  the 
ordinary  epithelial  cells  of  the  early  fossae  forms  neuroblasts.  The  latter 
become  bipolar,  forming  short  peripheral  and  longer  central  processes — 
the  olfactory  nerves.  Most  of  the  cell  bodies  of  the  neuroblasts  remain 
permanently  in  the  nasal  epithelium,  the  central  processes  grow  toward 
and  ultimately  into  the  olfactory  bulb  of  the  brain,  while  the  peripheral 
processes  project  to  the  free  surface  of  the  epithelium.  Some  of  the  neuro- 
blasts wander  somewhat  and  are  later  found  along  the  course  of  the  olfac- 
tory nerves.  Mihalkovics  found  that  at  first  all  portions  of  the  epithelium 
of  the  nasal  fossae  contain  olfactory  elements  and  connections.  Be  that 
as  it  may,  all  connections  with  the  olfactory  nerves  are  lost  save  in  the 
upper  part  of  the  fossae  (page  261).  The  non-olfactory  portions  of  the  fossae 
assume  the  role  merely  of  respiratory  passages.  At  a  subsequent  stage 
(third  month)  the  cartilaginous  cribriform  plate  of  the  ethmoid  is  formed 
around  the  olfactory  nerve  fibers  and  the  olfactory  bulb  is  placed  on  the 
cranial  side.  Ultimately  (seventh  or  eighth  month)  the  cribriform  plate 
ossifies  and  permanent  foramina  for  these  nerves  are  formed. 

The  Nasal  Glands. — The  glands  of  the  human  nose  develop  in  the 
third  month  of  fetal  life  as  solid  cords  and  mature  after  birth. 

The  Vomeronasal  Organ  (Jacobsonii). — The  vomeronasal  organ 
(Jacobsonii)  is  a  rudimentary  epithelial  structure  in  man  and  reaches  its 
maximum  development  in  the  fetus  at  approximately  the  twentieth  week, 
and  at  this  time,  according  to  Kallius,  receives  twigs  from  the  olfactory 
nerves.  Embryologically  it  appears  at  the  caudal  or  stomodceal  end  of 
the  olfactory  pit  as  a  blindly-ending  mucous-membrane  sac  (Fig.  9). 
After  the  caudal  closure  of  the  olfactory  pit  and  separation  of  the  latter 
from  the  mouth  cavity,  the  pocket-like  vomeronasal  organ  is  located  in  the 
nasal  septum  slightly  above  the  orifice  of  the  nasopalatine  canal.  It  now 
assumes  the  form  of  a  narrow  duct,  more  or  less  oval  in  transection  and 
courses  longitudinally  in  the  septal  tissue.  At  ten  weeks  of  embryonal 
life  one  finds  the  organ  bilaterally  present  with  an  approximate  depth 
of  0.48  mm.  After  this  it  varies  considerably.  Complete  degeneration  in 


48  GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 

early  fetal  life  may  ensue.  On  the  other  hand,  one  frequently  finds  the 
vomeronasal  organ  in  adult  man.  Special  supporting  cartilages  are  not 
developed  for  the  organ  in  man.  It  is  supplied  by  nerve  fibers  which  arise 
from  cells  in  its  own  epithelium  (apparently  not  in  adult  man),  also  by  the 
nervus  terminalis,  branches  of  the  trigeminal  nerve,  and,  according  to 
Read,  by  a  branch  of  the  olfactory  nerve,  at  least  at  the  time  of  birth 
(seepage  270). 

THE  EMBRYONIC  EXTERNAL  NOSE 

The  frontal  process,  one  of  the  cranial  trabeculae,  early  divides  into 
a  medial  frontal  process  and  into  two  lateral  frontal  processes.  As 
stated  elsewhere  (page  4)  this  division  is  initially  due  to  the  invagina- 
tion  (sinking  in)  of  the  surface  epithelium  in  the  formation  of  the  early 
nasal  or  olfactory  pits.  The  lateral  frontal  processes  are  in  reality  the 
lateral  nasal  processes.  Moreover,  the  middle  frontal  process  undergoes 
secondary  differentiation  into  the  right  and  left  medial  nasal  processes. 
The  maxillary  processes  then  grow  ventromedially  and  fuse  with  the 
medial  nasal  processes,  the  medial  and  lateral  nasal  processes  fuse  at  the 
caudal  border  of  the  nasal  pits,  and  the  lateral  nasal  and  maxillary  proc- 
esses fuse  along  the  line  of  the  naso-optic  furrow.  By  these  several 
fusions  of  embryologic  processes  the  upper  border  of  the  primitive  mouth 
cavity  is  formed  by  the  medial  nasal  and  the  maxillary  processes,  and  the 
ever  deepening  nasal  fossae  receive  definite  walls  or  boundaries. 

The  bucconasal  membranes  now  rupture  and  the  primitive  palate  is 
established,  and  with  it  the  medial  frontal  process  narrows  and  the  pre- 
viously widely  separated  nasal  fossae  are  brought  close  together.  Between 
the  buccalward-projecting  medial  nasal  processes  is  a  depressed  area 
which  His1  named  the  infranasal  area,  and  cephalic  to  the  latter  and  caudal 
to  the  head  prominence  caused  by  the  growing  cerebral  hemispheres  is 
the  triangular  area  of  His.  The  indefinite  area  between  the  triangular 
and  infranasal  areas  later  takes  form  and  gives  rise  to  the  border  and  tip 
of  the  nose.  The  triangular  area  becomes  the  dorsum  of  the  nose  and 
the  infranasal  area  is  modified  to  become  the  philtrum  of  the  upper  lip 
and  the  nasal  septum  between  the  nares.  The  combined  medial  nasal 
processes  extend,  of  course,  dorsad  as  the  intermaxillary  mass. 

The  external  nose  does  not  acquire  its  definite  individual  form  until 
after  birth;  indeed,  the  form  and  racial  characteristics  are  delayed  until 
after  puberty.  However,  by  the  end  of  the  second  month  of  embryo- 
logic  life,  the  external  nose  is  fairly  well  defined  as  a  broad,  flat  organ  and 

1  Anatomic  menschlicher  Embryonen,  Leipsig,  1885. 


NASOLACR1MAL  PASSAGEWAYS 


49 


is  limited  from  the  forehead  by  an  arched  groove.  The  dorsum  of  the 
nose  is  especially  active  in  taking  form  early  and  later  in  fetal  life  the 
nostrils  assume  a  more  caudal  and  horizontal  position  and  the  median 
portion  of  the  dorsum  grows  caudally  and  ventrally  to  become  the  tip  of 
the  nose.  In  the  newborn  the  bridge  of  the  nose  is  low  and  the  nose 
proper  relatively  broad  and  stumpy. 


nof 


FIG.  44. 


FIG.  45. 


f 


FIG.  46.  FIG.  47. 

FIGS.  44-47. — Photomicrographs  of  frontal  sections  of  the  heads  of  human  embryos  showing 
several  stages  in  the  development  of  the  nasolacrimal  passageways:  Fig.  44  aged  33  days;  Fig.  45 
aged  35  days;  Fig.  46  aged  36  days;  Fig.  47  aged  43  days.  X  7.  (After  J.  P.  5.) 

nof  =  Remains  of  naso-optic  furrow;  /  =  nasal  fossa;  e  =  eye;  d  =  different  stages  of  the  rudi- 
ment or  anlage  of  the  nasolacrimal  passageways. 

THE  NASOLACRIMAL  PASSAGEWAYS 

The  lacrimal  sac  (saccus  lacrimalis)  and  the  nasolacrimal  duct  (ductus 
nasolacrimalis)  are  in  no  way  connected  with  the  sense  of  smell.  How- 
ever, they  are  so  closely  related  to  the  nasal  fossa  that  a  note  concerning 
their  embryology  is  warranted  in  this  connection.  The  following  sum- 


5o  GENERAL  EMBRYOLOGY  AND  DEVELOPMENT 

mary  from  a  previous  publication  (see  Schaeffer,  American  Journal  of 
Anatomy,  Vol.  13,  No.  i,  1912)  on  the  genesis  of  the  nasolacrimal  passage- 
ways will  suffice : 

1.  The  strand  of  thickened  epithelium — the  rudiment  or  anlage  of  the 
nasolacrimal  passageways — along  the  floor  of  the  rudimentary  naso-optic 
fissure  becomes  entirely  separated  from  the  surface,  and  for  some  time  is 
wholly  surrounded  by  mesenchymal  tissue,  Figs.  44  to  48. 

2.  The  strand  or  cord  of  epithelial  cells  thus  isolated  from  the  surface 
is  for  some  time  without  a  lumen. 


Foxsa  rraii' 
anterior 


m 

4  .'••••;,   ' 


/ 


. 

'T 


PIG.  48. — Selected  sections  from  a  series  through  the  developing  nasolacrimal  passageways 
(human  embryo  aged  from  43  to  45  days).  Nowhere  is  the  rudiment  or  anlage  of  the  nasolacrimal 
passageways  in  connection  with  the  surface  epithelium.  The  "passageways"  are  solid  cords  of 
epithelial  cells  at  this  time  and  are  indicated  in  deep  black.  X  14.  (After  J.  P.  S.) 

3.  From  the  mother  cord  of  cells  both  lacrimal  ducts  and  the  nasal 
end  of  the  nasolacrimal  duct  grow  as  sprouts.  The  cephalic  portion  of 
the  lacrimal  sac  also  grows  as  a  sprout  from  the  mother  cord. 

4-  Considerable  variation  occurs  in  the  development  of  the  lacrimal 
ducts,  i.e.,  as  to  number,  time,  and  degree  of  development. 

5.  The  lumina  of  the  several  portions  of  the  nasolacrimal  passageways 
are  established  in  an  irregular  manner.  The  ocular  end  of  the  mother 


CONGENITAL  DEFECTS  51 

cord  is  the  first  to  establish  a  lumen.  The  point  of  coalescence  between 
the  nasal  end  of  the  cord  and  the  mucous  membrane  of  the  inferior  nasal 
meatus  is  the  last  to  become  patent — the  lumen  here  is  established  ap- 
proximately at  "term"  or  even  later.  The  horizontal  portions  of  the 
lacrimal  ducts  establish  lumina  before  the  vertical  portions. 

The  divers  types  of  ostia  nasolacrimalia  found  in  the  adult  are  in 
accord  with  the  potentialities  of  lumen  formation  at  the  point  of  fusion 
of  the  solid  epithelial  nasolacrimal  duct  with  the  mucous  membrane  of 
the  inferior  nasal  meatus.  The  place  and  degree  of  fusion  vary  consider- 
ably (Figs.  51,  52  D;  also  Schaeffer,  American  Journal  of  Anatomy,  Vol.  13, 
No.  2,  1912),  thus  leading  to  variously  located  ostia,  single  and  multiple 
ostia,  unguarded  and  "valved"  ostia. 

The  relations  of  the  nasolacrimal  ducts  to  the  nasal  fossae  and  the 
paranasal  sinuses  and  the  communication  of  the  ducts  with  the  inferior 
nasal  meatuses  are  discussed  under  the  proper  headings  in  connection  with 
the  adult  anatomy  (pages  252-253  and  Figs.  173  and  177). 

CONGENITAL  DEFECTS  OF  THE  NOSE 

The  manner  in  which  embryologic  epithelially-covered  mesenchymal 
processes  unite  in  the  formation  of  the  early  nose  and  roof  of  the  mouth 
is  illustrated  in  Fig.  3  in  which  the  medial  nasal  and  the  maxillary 
processes  are  undergoing  fusion.  At  places  the  epithelial  "union"  is 
entirely  lost  and  the  mesoblastic  tissue  bridges  or  heals  over  the  previous 
embryologic  fissure;  e.g.,  the  mesoblast  of  the  maxillary  process  is  con- 
fluent with  that  of  the  medial  nasal  process.  These  photographic  repre- 
sentations of  sections  from  a  human  embryo  illustrate  the  manner  in 
which  all  of  the  fissures  about  the  nose  and  mouth  are  obliterated.  Tf 
for  some  reason  fusion  of  the  several  processes  is  too  long  delayed,  con- 
tinued growth  of  the  several  elements  bordering  the  fissures  causes  them 
to  separate  and  once  the  breach  in  their  continuity  is  established  union 
cannot  take  place  subsequently.  Lack  of  fusion  and  separation  of  the 
several  processes  leads  to  the  malformations  known  as  cleft  palate  and 
harelip.  Divers  degrees  of  these  malformations  occur  both  unilaterally 
and  bilaterally. 

In  harelip  the  cleft  or  defect  may  appear  laterally  between  the  medial 
part  of  the  lip  formed  by  the  medial  nasal  processes  and  the  lateral  part 
of  the  lip  formed  by  the  maxillary  process  (lateral  harelip).  Should  the 
medial  nasal  and  lateral  nasal  processes  fail  to  unite  at  the  floor  of  the 
naris  (nostril)  the  lateral  harelip  would  be  continued  into  and  be  confluent 


- 


GENERAL  EMBRYOLOGY   AND  DEVELOPMENT 


-ild 


I* 


nld 


FIG.  51. 


FIG.  51. 

FIGS.  49-51. — Frontal  sections  through  the  nasolacrimal  passageways  of  a  human  embryo  aged 
107  days.  Note  that  both  lacrimal  ducts  (Fig.  49)  are  in  contact  and  fused  with  the  epidermis  in  the 
region  of  the  free  borders  of  the  eyelids,  but  that  the  ducts  have  not  established  lumina  at  all  points. 
The  remaining  portions  of  the  passageways  are  irregularly  patent  throughout,  save  that  the  connec- 
tion with  the  inferior  nasal  meatus  is  not  established  at  this  time  (Fig.  51).  (After  J.P.S.) 

sld  -  superior  lacrimal  duct;  ild  =  inferior  lacrimal  duct;  dd  =  common  lacrimal  duct;  Is  = 
lacrimal  sac;  nld  =  nasolacrimal  duct.  X  n. 


CONGENITAL  DEFECTS 


53 


with  the  nasal  vestibule.  Rarely  a  cleft  is  found  in  man  in  the  median 
line  of  the  upper  lip  due  to  a  lack  of  superficial  union  of  the  right  and  left 
medial  nasal  processes  (median  harelip) — a  condition  always  present  in 
the  upper  lip  of  the  hare. 

A 


FIG.  52. — Photomicrographs  of  frontal  sections  through  the  nasolacrimal  passageways  of  a 
human  embryo  aged  128  days.  Note  the  solid  portions  of  the  lacrimal  ducts  in  Pig.  A.  In  Fig.  B, 
we  have  a  patent  section  (Is)  of  the  ocular  end  of  the  nasolacrimal  duct  and  in  Fig.  C,  a  section  of  the 
mid-portion  of  the  nasolacrimal  duct  still  solid  (nld).  Note  the  well  established  lumen  (nld)  at 
the  nasal  end  of  the  nasolacrimal  duct  in  Figs.  D  and  E.  Note  how  extensive  the  contact  point 
between  the  nasolacrimal  duct  and  the  inferior  nasal  meatus  will  be  (Fig.  D).  sld  =  superior  lacrimal 
duct;  ild  =  inferior  lacrimal  duct;  Is  =  lacrimal  sac;  nld  =  nasolacrimal  duct;  inc  =  inferior  nasal 
concha;  inm  =  inferior  nasal  meatus.  X  19.  (After  J.  P.  S.) 

Normally  the  sockets  of  all  four  incisor  teeth  are  formed  by  the  pre- 
maxillae.     However,  in  some  cases  of  cleft  palate  the  sockets  of  the  right 


54  GENERAL    EMBRYOLOGY   AND   DEVELOPMENT 

and  left  lateral  incisors  are  attached  to  the  right  and  left  maxillae  proper, 
respectively — the  central  incisors  alone  appearing  on  the  premaxillae. 
Indeed,  the  lateral  incisor  may  occasionally  under  normal  conditions  have 
its  socket  in  the  maxilla.  Albrecht  erroneously  supposed  that  each  pre- 
maxilla  was  made  up  of  two  osseous  elements,  a  lateral  and  a  medial,  and 
that  in  cleft  palate  the  fissure  might  lie  between  these  supposed  elements 
of  the  premaxillary  or  between  the  premaxillary  and  the  maxillary  proc- 
esses. While  it  is  true  that  clefts  do  occur  in  both  of  these  positions  it 
is,  however,  obvious  that  cleft  palate  is  not  due  to  a  failure  of  osseous 
centers  to  coalesce,  but  to  a  non-union  of  pre-osseous  embryologic  masses. 
Each  premaxilla  has  a  single  ossification  center  as  pointed  out  by  Mall. 


PIG.  53. — Infant  with,  complete  harelip  on  left,  partial  on  right,  and  cleft  palate.  Note  the  pro- 
trusion of  premaxillary  bones  and  the  complete  isolation  of  the  vomer  from  both  palatal  plates. 
(After  Brophy.) 

Keith  finds  that  the  partial  suture  "which  may  divide  the  palatal  part  of 
the  premaxilla  is  due  not  to  two  centers  of  ossification,  but  to  the  formation 
of  the  palatal  part  by  two  processes  (pre-osseous),  one  corresonpding  to 
the  middle  incisor  socket,  the  other  to  the  lateral  incisor."  It  is  important 
to  keep  in  mind  that  the  rudiment  of  the  lateral  incisor  tooth  is  formed 
at  the  point  of  coalescence  of  the  medial  nasal  and  the  maxillary  processes 
and  in  the  event  that  these  processes  fail  to  merge  that  the  lateral  incisor 
tooth  rudiment  may  be  carried  "away"  by  either  the  maxillary  or  pre- 
maxillary elements  in  their  further  and  subsequent  separation  incident 
to  growth.  This  accounts  for  the  variability  in  the  location  of  the  lateral 
incisor  tooth  in  cleft  palate — now  in  the  maxilla,  again  in  the  premaxilla. 
Keith's  suggestion  that  the  palatal  portion  of  the  premaxilla  is  at  times  in 


CONGENITAL  DEFECTS 


55 


the  pre-osseous  stage  made  up  of  two  processes,  one  corresponding  to  the 
medial  incisor  rudiment,  the  other  to  the  lateral  incisor,  explains  the  occa- 
sional cleft  in  the  newborn  between  the  medial  and  lateral  incisors.  The 
fact  that  the  lateral  incisor  rudiment  may  be  carried  "away"  by  the 
maxillary  process  must  not  be  forgotten  in  this  connection. 

The  cleft  between  the  maxillary  process  and  the  medial  nasal  process 
may  not  involve  only  the  lip  and  the  alveolar  process,  but  may  extend 
dorsad  toward  or  to  the  incisive  canal.  Moreover,  it  may  continue  dorsad 
in  the  mid-sagittal  plane  in  the  formation  of  various  degrees  of  partial 
cleft  palate  or  if  carried  to  the  end  of  the  soft  palate  to  complete  cleft 
palate.  The  same  processes  may  be  operative  bilaterally,  fissuring  both 
sides  of  the  upper  lip  and  the  alveolar  processes  and  the  forward  portion  of 
the  palate  as  far  as  the  incisive  foramina,  and  if  occurring  simultaneously 


1 


FIG.  54. — Infant  three  months  old  with  complete  double  harelip.      (After  Brophy.) 

with  complete  fissuration  in  the  mid-saggital  plane  of  the  remaining  portion 
of  the  hard  and  soft  palates,  a  tripartite  palate  results.  If,  on  the  other 
hand,  the  fissuration  is  complete  dorsally  but  unilateral  ventrally,  the 
bipartite  palate  results.  As  stated  previously,  many  intermediate  degrees 
of  cleft  palate  occur,  Figs.  53  and  54. 

The  buccal  border  of  the  nasal  septum  may  or  may  not  be  adherent 
to  one  of  the  lateral  halves  of  a  cleft  palate.  If  attached  to  a  lateral  half  one 
of  the  nasal  fossae  would  be  closed  in  caudally  and  the  other  in  free  com- 
munication with  the  mouth  cavity.  In  the  event  that  the  septum  projects 
freely  in  the  roof  of  the  buccal  cavity,  both  nasal  fossae  are  in  wide  com- 
munication with  the  mouth  cavity.  Obviously,  the  degree  of  naso- 
buccal  communication  is  dependent  upon  the  degree  of  cleft  palate. 

It  is  not  the  province  in  this  connection  to  enter  into  the  details  of 
cleft  palate  and  harelip.  The  reader  is  referred  to  an  extensive  literature 


GENERAL  EMBRYOLOGY   AND   DEVELOPMENT 


on  the  subject,  especially  to  the  works  of  Keith,1  Inouye,2  His,3  Brophy,4 
Gaupp5  and  Schorr.6 

Congenital  absence  of  the  external  nose  is  a  very  rare  anomaly. 
Maisonneuve  reports  the  case  of  an  individual  in  which  the  projecting 
portion  of  the  nose  was  represented  by  an  even  surface,  perforated  by 
two  minute  apertures  three  millimeters  apart.  Roberts  reports  the 
case  of  an  infant  in  which  there  was  no  evidence  of  the  external  nose 
whatsoever,  even  the  narial  apertures  were  entirely  wanting.  Moreover, 
the  condition  was  associated  with  harelip  and  a  tripartite  palate. 

Exaggerations  in  volume  of  the  projecting  nose  are  not  infrequent. 
It  is  stated  that  one  Thomas  Wedders  had  a  nose  between  seven  and  eight 


FIG.   55. — Congenital  dermoid  in  a  female  child  aged  3  years.     The  tumor  was  noticed  directly 

after  birth. 

inches  long  and  was  exhibited  in  Yorkshire  early  in  the  last  century. 
Under-sized  external  noses  are  less  frequent.  The  writer,  however, 
recently  observed  a  nose  which  was  markedly  under-sized,  the  bridge  being 
but  little  elevated  above  the  plane  of  the  face.  Departures  from  what  may 
be  considered  normally  sized  external  noses  are  in  many  cases  merely 
individual,  family,  and  racial  characteristics  and  must  not  be  considered 
malformations.  Pathological  formations  must  not  be  confused  with  con- 
genitally  large  noses. 

British  Medical  Journal,  August,  1909. 
Anat.  Hefte,  Vols.  45  and  46,  1912. 
Anatomic  menschlicher  Embryonen,  Leipsig,  1885. 
Oral  Surgery,  Philadelphia,  1915. 
Anat.  Hefte,  Vol.  42,  1911. 
6  Anat.  Hefte,  Vol.  36,  1908. 


CONGENITAL  DEFECTS 


57 


Keith  cites  the  case  of  Kirchmayer  in  which  one  olfactory  pit  and 
the  lateral  nasal  process  formed  a  free  polypoid  body,  and  another  in 
which  the  condition  of  cyclops  with  both  nasal  fossae  enclosed  in  a  pro- 
boscis was  encountered. 

Congenital  occlusion  of  the  nares  due  to  epithelial  proliferation  with 
subsequent  organization  was  previously  referred  to  (page  10).  Similar 
occlusions  may  block  the  choanae.  However,  at  times  the  congenital 
occlusion  of  the  choanae  is  an  osseous  one.  One  readily  sees  how  ossifica- 
tion may  block  the  choanae  if  the  embryology  of  the  region  is  clearly 
kept  in  mind. 


FIG.  56. — Congenital  dermoid  fistula  in  a  girl  aged  21  years.     On  pressure  of  the  tumor  sebaceous 
matter  was  discharged  from  the  tunnel-like  opening  on  the  dorsum  nasi.     (Adapted  from  Krieg.) 

Flattened  or  depressed  alae  usually  accompany  harelip,  while  crooked 
noses  often  accompany  traumatic  or  spontaneous  deviations  of  the  nasal 
septum. 

Congenital  dermoids  on  the  bridge  of  the  nose  are  not  unknown. 
A  very  common  place  for  them  is  on  a  level  with  the  canthi  (Fig.  55). 
Moreover,  fistulae  of  congenital  dermoids  have  been  observed  at  various 
levels  on  the  dorsum  nasi,  Fig.  56. 


II-THE  DEFINITIVE  NOSE 


CHAPTER  II 
THE  DEFINITIVE  NOSE 

In  this  chapter  will  be  discussed  the  anatomy  of  the  fully  developed 
or  definitive  nose.  Even  after  puberty  certain  important  and  fundamental 
developmental  changes  take  place  in  the  nose  and  these  will  be  referred 
to  at  their  proper  places.  It  is  not  deemed  profitable  nor  essential  in 
this  connection  to  describe  the  detailed  osteology  of  each  individual  bone 
that  participates  in  the  make-up  of  the  osseous  cage  of  the  nasal  cavity. 
Suffice  it  in  subsequent  paragraphs  to  discuss  certain  of  the  more  impor- 
tant anatomical  points  of  individual  bones  and  more  especially  to  treat 
the  osseous  boundaries  of  the  nasal  fossae  as  a  whole.  The  paranasal 
(accessory)  sinuses  will  be  dealt  with  in  subsequent  and  separate  chapters. 

The  nose  consists  of  two  conspicuous  portions — the  external  nose 
(nasus  externus)  and  the  internal  nose  (nasus  internus).  The  latter,  more 
strictly  the  nasal  cavity,  is  divided  into  two  fossae  or  chambers  (fossae 
nasales)  by  the  nasal  septum  (septum  nasi).  Moreover,  the  nasal  fossae 
are  extended  by  the  nasal  meatuses  (meatus  nasi)  and  the  paranasal 
(accessory)  sinuses  (sinus  paranasales) .  The  nasal  conchae  (conchae  na- 
sales) configure  the  lateral  walls  of  the  nasal  cavity  and  further  increase 
the  surface  area  of  the  nasal  mucosa. 

THE  EXTERNAL  NOSE 

Individual  and  family  variations  of  the  external  nose  (nasus  externus) 
are  extremely  common  and  of  little  importance.  However,  entirely 
apart  from  individual  variation,  the  human  external  nose  is  readily 
grouped  into  several  more  or  less  distinct  anatomic  types.  The  root  of  the 
nose  forms  with  the  tissues  of  the  forehead  a  variable  obtuse  angle. 
Some  sort  of  a  frontonasal  angle  with  a  straight  dorsum  nasi  may  be 
taken  as  the  ground  type  of  nose  (straight  type  of  nose)  from  which  there 
are,  however,  definite  anatomic  departures.  If  the  frontonasal  angle  is 
wanting,  e.g.,  the  dorsum  of  the  nose  forms  with  the  tissues  of  the  forehead 
a  straight  angle,  the  Grecian  type  of  nose  is  produced.  The  dorsum 
of  the  nose  is  not  infrequently  convex,  giving  rise  to  the  nasus 
aduncus  or  aquiline  type  of  nose.  The  nasus  avicularis  or  Roman  nose 
and  the  Jewish  nose  are  variations  of  the  aquiline  type  due  to  modification 
of  the  angle  on  the  dorsum  nasi.  In  the  Jewish  nose  the  tip  is  depressed, 


62  THE  DEFINITIVE  NOSE 

with  a  resultant  general  forward  curvature  of  the  entire  dorsum  nasi. 
The  Roman  nose,  on  the  other  hand,  presents  a  rather  acute  angle  at  the 
point  of  confluence  of  the  bony  and  cartilaginous  portions  of  the  dorsum 
nasi  and  a  more  prominent  nasal  tip.  Another  type  of  nose  is  encountered 
when  the  dorsum  nasi  is  depressed  (concavity) .  This  leads  to  a  relatively 
prominent  nasal  tip  and  gives  rise  to  the  pug  or  saddle  type  of  nose  (the 
nasus  simus  or  nasus  nasicornis,  the  nez  retrousse  of  the  French).  Such 
an  individual  is  said  to  be  flat-nosed,  snub-nosed.  Topinard's  nasal  types 
are:  (i)  the  curved,  (2)  the  straight,  (3)  the  depressed  or  stumpy,  (4) 
the  Roman,  (5)  the  Jewish  or  aquiline,  Figs.  57-61. 

Topinard  and  others  have  shown  that  there  is  one  kind  of  variation 
which  is  of  considerable  anthropologic  importance,  e.g.,  the  degree  or 
lateral  expansion  of  the  nares  (anterior  nares)  as  compared  with  the  total 
length  of  the  nose.  This  relationship  is  expressed  by  the  cephalometric 


FIG.  57.  FIG.  58.  FIG.  59.  FIG.  60.  FIG.  61. 

FIGS.  57-61. — Topinard's  nasal  types.     Fig.  57,  Roman;  Fig.  58,  straight;  Fig.  59,  curved;  Fig.  60, 
depressed  or  stumpy;  Fig.  61,  Jewish  or  aquiline. 

greatest  breath  X  100 

nasal    index —  — • r, —  •     It  is  found  that  in  the  white  races 

greatest  length 

of  mankind  the  nasal  index  is  below  70  (leptorrhines),  giving  the  long,  high 
nose;  in  the  black  races  (African,  Australasian)  it  is  85  and  upward  (plat- 
yrrhines) ,  giving  the  short,  low  nose ;  and  in  the  red  and  yellow  races  (Asiatic, 
Eskimos,  American  Indians)  it  is  from  70  to  85  (mesorrhines),  giving  a 
type  intermediate  between  the  other  two.  The  nasal  index  is  sometimes 
determined  by  considering  the  length  of  the  nose  as  extending  from  the 
frontonasal  suture  to  the  anterior  nasal  spine.  Then  the  leptorrhine  index 
is  below  48,  the  mesorrhine  from  48  to  55,  and  the  platyrrhine  above  55. 
The  latter  index  obviously  does  not  utilize  the  greatest  length  of  the  nose. 

The  external  nose  forms  a  conspicuous  triangular  pyramid  that 
projects  from  a  point  below  the  glabella,  ventral-  and  caudal  ward  to 
terminate  in  a  free  angle.  The  cephalic  end  is  referred  to  as  the  root 
(radix  nasi)  and  the  free  angle  as  the  point  or  apex  (apex  nasi).  Con- 
necting the  two  extremities  in  the  form  of  a  rounded  median  ridge  is  the 


BONES  OF  EXTERNAL  NOSE  /     63 


dorsum  nasi.  The  cephalic  part  of  the  dorsum  is  supported  by  the  nasal 
bones  and  is  here  called  the  bridge  of  the  nose.  The  lateral  surfaces  of 
the  nose  (partes  laterales  nasi)  extend  from  the  dorsum  to  become  con- 
fluent with  the  tissues  of  the  face  proper  (nasofacial  angles)  and  distally 
they  end  in  rounded  eminences,  the  alae  nasi,  which  form  with  the  upper 
lip  the  nasolabial  sulci.  The  base  of  the  nasal  pyramid  is  pierced  by  two 
openings,  the  nostrils  or  nares  (anterior  nares) .  The  entire  external  nose 
is  supported  by  a  bony  and  cartilaginous  framework  and  covered  by  skin 
and  muscles  (Fig.  68). 


FIG.  62. — The  osseous  pyriform  aperture  of  the  nasal  cavity.      Note  the  conchal  cell  (ethmoidal  cell) 

in  the  concha  nasalis  media. 
On   =  os  nasale;  M   =  maxilla;  Cc   =  conchal  cell;  Sna   =  spina  nasalis  anterior. 

The  Bones  of  the  External  Nose. — The  bones  that  participate  in 
giving  shape  and  support  to  the  external  nose  are  the  nasal  bones  (the 
nasal  bridge),  the  maxillae,  and  the  nasal  part  (pars  nasalis)  of  the  frontal 
bone.  The  latter  occupies  the  ventral  portion  of  the  ethmoidal  notch 
and  projects  beneath  the  nasal  bones  and  the  frontal  processes  of  the 
maxillae,  thus  lending  support  to  the  bridge  of  the  nose.  The  arch-like 
construction  in  the  coronal  plane  of  the  nasal  bones  and  the  frontal  proc- 
esses of  the  maxillae  is  in  itself  reasonably  strong.  Moreover,  the  elements 
that  enter  into  the  composition  of  the  nasal  septum  act  as  a  unit  in  suppor- 
irig-the  entire  dorsum  of  the  nose. 

The  palr^d^&qsa/  bone  (os  nasale)Js^evelep€driri  membrane  (accord- 


64  THE  DEFINITIVE  NOSE 

ing  to  Perna  and  Livini,  in  membrane  and  cartilage,  see  page  42  on  the  ossi- 
fication of  the  nasal  bone).  The  adult  bone  is  narrow  and  robust  above, 
but  becomes  thinner  and  wider  at  its  lower  extremity.  The  serrated 
cephalic  border  (margo  frontalis)  articulates  with  the  medial  portion  of 
the  nasal  margin  (margo  nasalis)  of  the  frontal  .bone  and  the  notched 
caudal  border  in  the  dried  skull  is  free  and  in  the  recent  state  gives  at- 
tachment to  the  lateral  nasal  cartilage.  The  longer  lateral  border  (margo 
maxillaris)  articulates  with  the  frontal  process  (processus  frontalis)  of 
the  maxilla.  The  median  border  (margo  nasalis)  is  robust  above  and  less 
so  below  and  articulates  with  its  fellow  of  the  opposite  side  in  the  forma- 
tion of  the  internasal  suture.  Entally  the  two  nasal  bones  conjointly 
form  a  crest  (crista  nasalis)  to  meet  with  the  frontal  spine  (spina  frontalis) 


Ona.- 


FIG.   63. — A  drawing  of  a  specimen  showing  asymmetrical  nasal   bones;   also   an   accessory   nasal 

bone. 
On   =  os  nasale;  Ona   =  os  nasale  accessoria. 

of  the  frontal  bone,  the  perpendicular  plate  (lamina  perpendicularis)  of 
the  ethmoid  bone,  and  the  septal  cartilage  (cartilage  septi  nasi).  The 
ental  or  nasal  surface  at  its  cephalic  end  articulates  with  the  frontal  bone, 
elsewhere  it  is  concave  and  smooth  and  is  invested  by  the  nasal  mucosa. 
This  surface  is  grooved — the  sulcus  ethmoidalis,  for  the  nasal  branch  of  the 
naso-ciliary  nerve.  The  ectal  or  facial  surface  is  concave  from  above  down- 
ward for  a  considerable  distance,  caudally  it  is  convex  (Figs.  62  and  66). 
The  foregoing  description  of  the  normal  nasal  bones  is  deemed  ad- 
visable since  departures  from  the  normal  are  not  infrequent.  In  X-ray 
photographs  and  in  visual  and  manual  examinations  of  the  bridge  of  the 
nose  due  consideration  must  be  given  to  variations  in  the  osteology  of 
the  nasal  bridge  lest  faulty  interpretations  be  given. 


NASAL  BONES 


The  shape  and  measurements  of  the  nasal  bones  vary  greatly  hi 
different  individuals.  Generally  speaking,  they  are  relatively  large  and 
prominent  in  the  white  races  and  small  and  less  prominent  (flat)  in  the 


FIG.  64. — A  drawing  of  a  specimen  showing  complete  agenesis  or  absence  of  the  nasal  bones, 
also  a  detached  osseous  element  of  the  frontal  bone  (Of).  Particularly  note  that  the  nasal  bones  are 
replaced  by  the  nasal  or  frontal  processes  (PfM)  of  the  maxillae. 

dark  and  yellow  races.  Ape-like  the  two  nasal  bones  in  man  at  times 
fuse  by  obliteration  of  the  internasal  suture.  The  bones  are  frequently 
variously  reduced  in  size  and  altered  in  shape  by  encroachment  of  the 


PfJZ... 


FIG.  65. — A  drawing  of  a  specimen  showing  complete  agenesis  or  absence  of  the  nasal  bones  but 
in  which  the  mesethmoid  (Me),  e.g.,  the  perpendicular  lamina  (vertical  plate)  of  the  ethmoid  bone, 
comes  to  the  surface  between  the  frontal  processes  (PfM)  of  the  maxillae  which  replace  the  nasal 
bones. 

frontal  processes  of  the  maxillae.     Indeed,  the  latter  may  reduce  the  nasal 
bones  to  a  mere  mid-sagittal  ridge  or  replace  them  altogether  by  articulat- 


66  THE  DEFINITIVE  NOSE 

ing  with  each  other  in  the  formation  of  the  nasal  bridge  (like  the  catar- 
rhine  monkeys).  The  author  has  in  his  collection  a  human  skull  in  which 
both  nasal  bones  are  absent,  the  perpendicular  plate  of  the  ethmoid  bone 
coming  to  the  surface  in  the  mid-sagittal  plane  between  the  frontal  proc- 
esses of  the  maxillae  (often  seen  in  the  orang).  Medial  projections  of 
the  frontal  bone  rarely  replace  the  nasals.  Furthermore,  each  nasal 
bone  may  appear  as  several  pieces  or  may  be  divided  by  a  vertical  fissure. 
Additional  ossicles  are  occasionally  found  in  the  line  of  the  internasal 
suture  or  between  the  nasal  and  neighboring  bones.  The  subjacent  carti- 
lage of  the  nasal  capsule  may  ossify  at  places  and  form  minute  plates  of 
bone  beneath  the  adult  nasals  proper.  Again,  the  nasal  bones  are  elon- 
gated and  bound  the  pyriform  nasal  aperture  along  its  lateral  margins. 
Rarely  the  nasal  bones  are  absent  and  the  place  filled  in  by  membrane 
(Figs.  63,  64  and  65). 

In  the  skeleton  the  nasal  fossae  open  externally  on  the  face  region  by 
more  or  less  asymmetrical  pyriform  apertures  which  conjointly  form 
an  inverted,  cordiform-shaped  opening  at  a  level  distinctly  above  the 
nares  of  the  nose  (in  the  recent  state) .  The  floor  of  the  wider  aperture  is 
usually  at  a  somewhat  higher  plane  than  that  of  the  narrower  one.  The 
cordiform  aperture  is  bounded  cephalically  by  the  free  border  of  the  nasal 
bones  and  elsewhere  by  the  maxillae.  As  stated  elsewhere,  the  nasals  at 
times  project  caudally  along  the  lateral  walls  of  the  cordiform  aperture. 
In  the  mid-sagittal  plane,  and  projecting  ventrad  from  the  floor  of  the 
aperture,  is  the  prominent  anterior  nasal  spine,  usually  directed  toward 
the  widest  aperture  (Fig.  161). 

Usually  the  floor  of  the  aperture  is  dull  and  rounded  and  directly 
continuous  with  its  sharp  lateral  border.  Occasionally,  however,  in 
the  adult  and  nearly  always  in  the  infant  and  low  races,  extending  from 
the  lateral  margin  of  the  incisor  crest  and  anterior  nasal  spine  are  two 
bony  ridges,  the  ventral  one  confluent  with  the  ventral  surface  of  the 
maxilla  and  the  dorsal  one  coursing  inside  the  nose  ventral  to  the  inferior 
turbinated  crest.  These  two  ridges  enclose  a  distinct  depression — the 
fossa  prenasalis,  on  the  face,  immediately  below  the  bony  nasal  aper- 
ture. However,  as  a  rule  the  identity  of  the  two  lines  is  lost  by  fusion  in 
the  adult.  Variations  are  encountered. 

The  Cartilages  of  the  External  Nose.— As  stated  above,  the  pyriform 
aperture  (apertura  pyriformis)  of  the -dried  and  prepared  skull  is  bounded 
by  the  free  borders  of  the  nasal  bones  and  the  maxillae.  In  the  recent  state 
this  aperture  is  enclosed  and  continued  to  the  nares  or  nostrils  (anterior 
nares)  by  the  nasal  cartilages  and  contiguous  tissues.  Four  major  carti- 


CARTILAGES  OF  EXTERNAL  NOSE 


FIG.  66. — An  adult  skull  with  the  individual  bones  separated.  Note  the  metopic  suture  and  that 
the  frontal  sinuses  do  not  extend  beyond  the  midline,  the  usual  anatomy  in  such  cases.  The  maxil- 
lary and  frontal  sinuses  are  shown  in  dotted  outline. 


68 


THE  DEFINITIVE  NOSE 


lages  (cartilagines  majores)  participate  in  the  formation  of  the  framework 
of  the  external  nose.  Moreover,  a  variable  number  of  minor  or  accessory 
cartilages  (cartilagines  minores)  are  usually  found.  The  major  cartilages 
are  the  paired  lateral  and  greater  alar  cartilages.  The  accessory  elements 
are  the  accessory  alar  cartilages  and  the  sesamoid  cartilages.  Although 
the  unpaired  septal  cartilage  and  the  vomeronasal  cartilages  of  Jacobson 
likewise  assist  directly  or  indirectly  in  the  support  of  the  external  nose 
they  will  be  discussed  in  connection  with  the  nasal  septum. 

' 


FIG.  67. — The  cartilages  of  the  external  nose  as  displayed  (frontal  view)  after  the  removal  of  the 

skin  and  muscles. 

Cam  =  cartilagines  alares  minores;  C.  ses.  n  =  cartilagines  sesamoideae  nasi;  Csn  =  cartilago 
septi  nasi;  Cnl  =  cartilago  nasi  lateralis;  Camaj  (Cl)  =  cartilago  alaris  major  (crus  laterale).  Snm  = 
sutura  nasomaxillaris. 

The  division  of  the  major  nasal  cartilages  is,  in  a  sense,  arbitrary  and 
unwarranted.  As  mentioned  previously,  in  connection  with  the  embry- 
ology and  morphology  of  the  cartilaginous  nasal  capsule,  the  three  major 
nasal  cartilages  (two  paired,  one  unpaired)  constitute  one  piece  (cartilagino 
mediana  nasi).  The  lateral  nasal  cartilages  and  the  septal  cartilage 
remain  connected  in  the  adult,  while  the  greater  alar  cartilages  become 
disconnected  and  appear  as  independent  elements. 

The  greater  alar  cartilage  (cartilago  alaris  major)  partially  encircles 
the  ventral  part  of  the  naris  (nostril),  assists  in  keeping  the  naris  and 


CARTILAGES  OF  EXTERNAL  NOSE 


69 


vestibule  open,  and  with  its  fellow  gives  shape  to  the  base  of  the  nose. 
The  cartilage  consists  of  two  crura — one  medial  (crus  mediale)  and  one 
lateral  (crus  laterale),  in  relation  to  the  naris.  The  crura  are  continuous 
with  each  other  at  the  apex  of  the  nose,  giving  the  latter  a  rounded  contour. 
The  interval  between  the  lateral  crus  of  the  cartilage  and  the  maxilla  is 
filled  in  by  a  strong  sheet  of  fibrous  tissue  in  which  are  embedded  the  lesser 
alar  cartilages.  At  times  the  lateral  crus  is  prolonged  dorsolaterally  so 
as  to  replace  the  lesser  cartilages.  Moreover,  the  lateral  crus  is  bound 
to  the  lateral  cartilage  by  a  fibrous  membrane  and  to  the  caudoventral 


,Cctm,in 
,.Cnl 
s-Csn 

Caartty 
''    (Cl) 

^.,  Carney 
' 

Ccancy 

(Cm.) 

~~- Sinn, 


FIG.  68. — The  cartilage  of  the  external  nose  as  displayed  (profile  view)  after  the  removal  of  the 

skin  and  muscles. 

On  =  os  nasale;  Camin  =  cartilagines  alares  minores;  Cnl  =  cartilage  nasi  lateralis;  Csn  = 
cartilagines  sesamoideae  nasi;  Camaj  (Cl)  =  cartilago  alaris  major  (crus  laterale);  Camaj  =  cartilago 
alaris  major;  Camaj  (Cm)  =  cartilago  alaris  major  (crus  mediale) ;  Smn  =  septum  mobile  nasi. 

part  of  the  cartilaginous  septum.  Toward  the  median  plane  the  lateral 
crus  is  curved  backward  to  form  the  medial  crus.  Here  the  latter  bounds 
a  deep  median  groove,  meets  with  its  fellow  of  the  opposite  side  and 
extends  dorsalward  in  the  columna  nasi  caudal  to  the  cartilage  of  the 
septum.  The  medial  crus  ends  dorsally  in  a  free,  out-turned  border 
(Figs.  67,  68). 

The  lateral  nasal  cartilage  (cartilago  nasi  lateralis)  is  a  flattened, 
triangular  plate  located  in  the  middle  part  of  the  lateral  surface  of  the 


7o  THE  DEFINITIVE  NOSE 

projecting  portion  of  the  nose,  immediately  distal  to  the  free  border  of 
the  nasal  bone.  One  surface  looks  toward  the  nasal  cavity  and  the  other 
ventrolaterally  toward  the  external  face.  The  dorsal  edge  or  border  of 
the  cartilage  is  thin  and  is  attached  to  the  maxilla  and  to  the  nasal  bone ; 
its  ventral  border  is  thick  and  above  directly  continuous  with  the  cartilage 
of  the  septum.  As  stated  before,  its  lower  edge  is  attached  by  fibrous 
tissue  to  the  upper  edge  of  the  lateral  crus  of  the  greater  alar  cartilage 
(Figs.  67  and  68). 

The  lesser  alar  cartilages  (cartilagines  atares  minores)  are  small  and 
variable  in  number.  They  are  found  bilaterally  embedded  in  the  strong 
fibrous  tissue  of  the  wing  of  the  nose  in  the  interval  between  the  lateral 
crus  of  the  greater  alar  cartilage  and  the  maxilla.  Sometimes  a  dorso- 
lateral  extension  of  the  lateral  crus  of  the  greater  aiar  cartilage  replaces 
the  lesser  alar  cartilages  in  part  or  in  whole  (Fig.  67). 


PIG.   69. — The  cartilages  of  the  nose  as  related  to  the  nares  (anterior  nares)  or  nostrils. 
Cam  =  cartilage   alaris   major    (Cl  =  crus   laterale,    Cm  =  crus   mediale) ;    Csn  =  cartilago    septi 
nasi;   Smn  =  septum   mobile   nasi   (columna   nasi);   Vn  =  vestibulum  nasi;   Ln  =  limen   nasi,  limen 
vestibuli;  2V   =  naris. 

The  sesamoid  nasal  cartilages  (cartilagines  sesamoideae)  of  the  nose 
when  present  are  located  in  the  interval  between  the  lateral  nasal  and 
septal  cartilages  medially  and  the  lateral  crus  of  the  greater  alar  cartilage 
laterally.  They  are  very  small  and  vary  in  number  from  one  to  three  or 
more  (Fig.  67). 

The  Muscles  of  the  External  Nose. — The  position  of  the  alae  of  the 
nose  can  be  altered  by  the  attached  muscles  and  facial  expression  modified 
thereby.  The  pars  transversa  of  the  nasalis  (compressor  nares) ;  the  caput 
angulare  of  the  quadratus  labii  superioris  (levator  labii  superioris  alaeque 
nasi) ;  and  the  dilatores  naris,  anterior  and  posterior,  elevate  and  dilate  the 


INTERNAL  NOSE  71 

naris  (nostril).  The  pars  alaris  of  the  nasalis  (depressor  alae  nasi)  and 
the  depressor  septi  nasi  depress  and  contract  the  naris.  Poirier  and 
Duchenne  found  that  the  pars  transversa  and  the  caput  angulare  act 
conjointly  in  drawing  laterally  and  cephalically  the  lateral  margin  of  the 
ala  of  the  nose,  the  position  of  the  nostril  expressing  sensuality.  When 
the  pars  transversa  acts  with  the  pars  alaris  it  may  constrict  the  naris. 
Expressions  of  pain  and  anger  are  brought  about  by  the  pars  alaris  and 
the  depressor  septi  nasi.  The  reader  is  referred  to  more  extensive  trea- 
tises on  facial  expression  and  anthropology  for  details. 

In  conclusion  the  author  wishes  to  urge  the  great  cosmetic  impor- 
tance of  the  external  nose  and  that  a  knowledge  of  the  types  of  face  and 
nose,  of  the  osseous  and  cartilaginous  nasal  framework,  of  the  nasal  mus- 
cles and  the  blood  and  nerve  supply  is  essential  to  those  dealing  with 
deformities  and  injuries  of  the  organ;  especially  so  since  plastic  surgery 
of  the  face  is  now  very  much  in  the  foreground. 

THE  INTERNAL  NOSE 

The  anatomy  of  the  internal  nose  (nasus  internus)  is  that  of  the 
nasal  cavity  (cavum  nasi)  and  ancillary  structures.  The  general  nasal 
cavity  is  divided  by  a  median  septum  (septum  nasi)  into  two  more  or  less 
symmetrical  halves — the  nasal  fossae  (fossae  nasales).  Moreover,  the 
fossae  are  further  divided  into  nasal  meatuses  (meatus  nasi)  by  the  nasal 
conchae  or  turbinates  (conchae  nasales)  and  are  extended  into  neighbor- 
ing bones  by  the  paranasal  (accessory)  sinuses  (sinus  paranasales) .  The 
fossae  communicate  with  the  exterior  through  the  nares  (anterior  nares) 
and  with  the  nasopharynx  dorsally  through  the  choanae  (posterior  nares). 
Conforming  with  the  more  specific  functions,  the  nasal  fossae  are  divided 
into  respiratory  and  olfactory  portions,  e.g.,  pars  respiratoria  and  pars 
olfactoria  respectively. 

There  is  great  variation Tin /.the  degree  of  deveTopmenT'and  complexity 
of  the  nasal  fossae  and  contained  structures  and  the  olfactory  lobes  in 
mammals.  This  led  Turner  to  divide  them  into  three  subdivisions: 
macrosmatics  (rodents,  carnivora,  marsupials  and  most  mammals); 
anosmatics  (certain  cetacea- — porpoise);  and  microsmatics  (man,  most 
primates  and  some  cetacea). 

Each  nasal  fossa  is  roughly  triangular  in  frontal  or  coronal  section. 
The  narrow  roof  of  the  fossa  may  be  considered  the  apex  of  the  triangle 
and  the  wider  floor  the  base.  The  median  wall  is  usually  unbroken  and 
even  and  approximately  vertical,  meeting  the  floor  at  nearly  a  right  angle. 


7  2  THE  DEFINITIVE  NOSE 

The  lateral  wall,  the  hypotenuse  of  the  triangle,  is  sloping  and  is  config- 
ured by  the  major  and  minor  nasal  conchae  and  meatuses  and  by  the 
impinging  paranasal  sinuses.  In  sagittal  section  the  contour  of  the  nasal 
fossa  represents  a  quadrangle,  the  cephalic  side  or  roof  of  which  is  approxi- 
mately parallel  to  the  caudal  side  or  floor.  The  ventral  or  anterior  side 
of  the  quadrangle  conforms  to  the  profile  of  the  external  nose  and  forms 
with  the  caudal  side  or  floor  an  acute  angle  at  the  naris.  The  dorsal  side 
falls  along  the  ventral  surface  of  the  body  of  the  sphenoid  bone,  then  passes 
through  the  choana  (posterior  naris)  in  front  of  the  ostium  pharyngeum 
of  the  tuba  auditiva  (Eustachian  tube)  to  impinge  upon  thedorsum  of 
the  junction-point  between  the  hard  and  soft  palates.  Laterally  the 
dorsal  limit  of  the  nasal  fossa  is  indicated  by  the  nasal  sulcus  (sulcus 
nasalis  posterior)  which  extends  from  the  angle  formed  by  the  confluence 
of  the  ventral  and  caudal  surfaces  of  the  body  of  the  sphenoid  bone  to  the 
junction  of  the  hard  and  soft  palates. 

There  is  considerable  variation  in  the  dimensions  of  the  nasal  fossae. 
The  type  of  nose  and  the  degree  of  arching  of  the  palate  obviously  must 
affect  the  dimensions  of  its  chambers.  The  degree  of  development  of  the 
nasal  conchae  and  the  size,  shape  and  disposition  of  the  paranasal  sinuses 
affect  the  symmetry  of  the  nasal  fossae  in  the  same  individual  and  in  dif- 
ferent individuals.  The  following  may  be  taken  as  representative  dimen- 
sions based  upon  a  large  series  of  specimens  studied  by  the  writer:  The 
greatest  sagittal  diameter,  measured  from  the  most  prominent  part  of 
the  naris  along  the  floor  of  the  nasal  fossa  to  the  dorsal  border  of  the  hard 
palate,  is  74  mm.,  while  the  extreme  sagittal  diameter  measured  along  the 
roof  of  the  fossa  is  but  35  mm.  or  less.  The  greatest  height  (vertical 
diameter)  is  found  by  dropping  a  perpendicular  line  from  the  ventral 
third  of  the  cribriform  plate  of  the  ethmoid  bone  to  the  floor  of  the  nasal 
fossa — averaging  from  40  to  45  mm.  The  nasal  fossa  is  a  mere  cleft  in 
the  coronal  or  frontal  plane  (width)  along  the  cribriform  plate  (roof) — 
3  mm.  or  less.  The  widest  part  of  its  floor  varies  from  12  to  23  mm., 
measured  at  the  greatest  lateral  expansion  of  the  inferior  nasal  meatus. 
The  width  of  the  floor  in  advance  of  the  knee  of  the  inferior  nasal  concha 
is  much  reduced — 4  mm.  or  less.  It  is  well  to  remember  that  after  the 
normal  point  of  constriction  is  passed  the  inferior  nasal  meatus  is  much 
more  roomy. 

The  Nares  (nostrils,  anterior  nares) . — The  nares  of  man  are  remark- 
able on  account  of  their  position,  looking  as  they  do  almost  directly  caudal- 
ward.  The  base  of  the  nose  varies  considerably.  Individual  variations 
are  extremely  commonplace  and  not  important.  There  are,  however, 


CHOANAE  73 

several  anatomic  types  which  are  of  anthropologic  interest  and  impor- 
tance. When  the  tip  of  the  nose  is  depressed  the  transverse  diameter 
through  the  alae  is  great  and  the  greatest  diameter  of  the  nares  is  placed 
horizontal,  e.g.,  in  the  black  races.  In  those  cases  where  the  tip  of  the 
nose  is  fairly  prominent,  as  in  the  white  races,  the  transverse  diameter 
through  the  alae  is  lessened  and  the  nares  are  nearly  in  the  sagittal  plane 
in  the  greatest  diameter.  The  inter-alar  distance  is  less  in  the  red  and 
yellow  races  than  in  the  black  races  and  the  nares  here  occupy  a  half- 
way position  between  the  horizontal  and  the  sagittal  planes. 

The  Vestibule  (vestibulum  nasi). — The  paired  vestibule  may  be 
considered  an  antechamber  to  the  nasal  fossa.  It  corresponds  more 
or  less  in  its  extent  to  the  cartilaginous  nasal  wall.  The  vestibule  is 
located  immediately  ental  to  the  aperture  of  the  naris  (nostril)  and  is 
supported  by  the  medial  and  lateral  plates  of  the  great  alar  cartilage  and 
adjacent  portions  of  the  nasal  septum  and  integument.  The  extension 
of  the  vestibule  into  the  tip  of  the  nose  is  often  referred  to  as  the  ventricle 
of  the  vestibule  (recessus  apicis).  The  deepest  and  lateral  boundary 
of  the  vestibule  is  formed  by  the  upper  and  arching  border  of  the  lateral 
plate  of  the  great  alar  cartilage  and  the  lower  border  of  the  lateral  cartilage. 
The  cartilages  throw  the  overlying  tissues  into  a  prominent  ridge,  form- 
ing with  the  cartilages  the  limen  vestibuli  or  the  limen  nasi  (Fig.  197). 
At  the  latter  the  skin  lining  the  vestibule  suffers  a  transition  into  the  mu- 
cous membrane  lining  the  nasal  fossa  proper  (see  nasal  mucous  membrane, 
page  261).  The  skin  lining  the  vestibule  is  supplied  with  hairs  (vibris- 
sae) — stout  and  coarse  immediately  within  the  naris  and  short,  slender  and 
scattered  elsewhere,  and  with  sudoriferous  and  sebaceous  glands.  Both 
the  hairs  and  glands  are  wanting  near  the  limen  nasi. 

The  Choanae  (posterior  nares) . — The  definitive  choanae  are  the  com- 
municating passageways  between  the  nasal  fossae  and  the  nasopharynx 
(Fig.  141).  The  nasal  meatuses  and  the  dorsal  extremities  of  the  nasal 
chonchae  converge  toward  the  dorsal  apertures.  However,  the  conchae 
are  from  10  to  12  mm.  in  advance  of  the  choanae  and  do  not  configure  the 
outlines  of  the  openings  as  they  do  the  lateral  nasal  walls.  The  dorsal 
extremities  of  the  nasal  conchae  can  be  inspected  through  the  choanae, 
especially  the  inferior  and  middle.  The  definitive  choanae  are  located 
farther  dorsad  than  the  primitive  choanae  which  connect  the  early  nasal 
fossae  with  the  mouth  cavity  (see  embryology,  page  9).  The  choanae 
are  bounded  cephalically  (above)  by  the  alae  of  the  vomer;  laterally  by 
the  median  plates  of  the  pterygoid  processes  of  the  sphenoid;  medially 
by  the  vomer;  and  caudally  (below)  by  the  horizontal  plate  of  the  palate 


74 


THE   DEFINITIVE  NOSE 


bone.  The  muco-periosteum  over  this  osseous  framework  is  continued 
from  the  nasal  fossae  into  the  pharynx.  The  osseous  boundaries  of  the 
choanae  cause  the  nasopharyngeal  communications  to  be  permanently 
open  and  free  unless  blocked  by  other  structures,  e.g.,  adenoids,  etc.  The 
author  observed  a  case  of  congenital  atresia  of  the  choanae  in  a  term  child. 
Such  atresia  may  be  the  result  of  an  organization  of  epithelial  plugs  which 
occasionally  block  the  choanae  earlier  in  fetal  life,  rarely  osseous  tissue 
develops  in  the  organization  (Fig.  70). 

The  vertical  diameter  of  the  adult  choanae  is  always  greater  than  the 
transverse  (coronal)  ;  the  comparison  being  shown  by  the  choanal  index  — 

transverse  diameter  X  100  .    . 

-.     ,  j.  -  •      The  author  found  the  index  for  the  male  to 

vertical  diameter 


of  clioa.no,  CoftcTtsz.  nasalis  media, 


I 

/  i 

Septum   TIMSI  ''  Concha.  nasaZis  inferior 

FIG.    70. — Congenital  atresia  of  the  right  choana  in  a  girl  aged   19  years  with  an  accompanying 
anosmia  of  the  right  side.      (After  Krieg.) 

be  6 1  and  for  the  female  64.5.  In  this  he  is  in  close  agreement  with 
Escat1  who  gives  60  for  the  male  and  64  for  the  female.  While  there 
may  be  slight  differences  in  the  diameters  of  the  choanae  of  the  two  sides, 
they  are  alike  in  this  regard  to  a  remarkable  degree.  The  transverse 
diameter  is  greater  at  the  floor  (varying  from  12  to  17  mm.)  and  least  at 
the  roof  (varying  from  7  to  10  mm.).  The  vertical  diameter  varies  from 
24  to  33  mm.  The  vertical  diameter  is  relatively  much  reduced  in  the 
newborn  child.  There  is  considerable  variation  in  the  inclination  of  the 
dorsal  free  border  of  the  vomer,  and  as  Dwight  has  shown  it  is  in  direct 
ratio  to  the  degree  of  prognathism.  The  gnathic  index  is  the  ratio  of  the 
line  from  the  basion  to  the  alveolar  point  to  the  line  from  the  basion  to 

1  Cavite  Naso-Pharyngiene,  Paris,  1894. 


FLOOR  OF  NASAL  CAVITY  75 

basi-alveolar  line  X  100 
the  nasion,  e.g.,  ---  r  —  •  -  -p  p  --     •   An  index  below  98  indicates  an 

orthognathic  skull;  98   to   103,  a  mesognathic  skull;  and  above  103,  a 
prognathic  skull. 

The  Floor  of  the  Nasal  Cavity.  —  The  osseous  framework  of  the  nasal 
floor  is  formed  by  the  palatal  processes  of  the  maxillae  and  the  horizontal 
processes  of  the  palate  bones,  Fig.  7  1  .  The  floor  of  the  nasal  cavity  serves 
also  as  the  roof  of  the  mouth.  The  broad  palate  is  usually  less  vaulted 
than  the  narrow  one.  The  ratio  of  the  breadth  to  the  length  is  expressed 

breadth  X  100 
by  the  palatal  index,  e.g.,  --  ,  -  rr  ------  ;  the  breadth  being  measured 

through  the  sockets  of  the  second  molar  teeth  and  the  length  from  the 
alveolar  process  in  the  mid-sagittal  plane  to  the  posterior  nasal  spine. 


Srn. 


Sna, 


FIG.  71.  —  A  dissection  illustrating  the  floor  of  the  nasal  fossae  as  related  to  the  maxillary  sinuses. 

Snp  =  spina    nasalis    posterior;    Sm  =  sinus    maxillaris;     Ci  =  canalis    incisivus;    Sna  =  spina 

nasalis  anterior;  PpM  =  processus  palatinus  maxillae;  PhOp  =  processus  horizontalis  ossis  palatini. 

The  generalization  often  made  that  narrow  palatal  arches  invariably 
lead  to  correspondingly  narrow  nasal  floors  is  unwarranted.  It  is  in  very 
many  instances  assuming  what  is  not  a  cause  for  narrow  nasal  floors  to 
be  a  cause  —  non  causa  pro  causa.  The  writer1  first  noticed  the  fallacy 
of  the  general  inference  or  premise  when  studying  the  relations  of  the  max- 
illary sinus  to  the  nasal  floor  (1907-10).  Since  then  many  observations 
have  been  made  to  show  that  the  nasal  floor  and  the  palatal  arch  are  not 
necessarily  synchronously  wide  or  narrow.  Wide  palatal  arches  may  be 
accompanied  by  relatively  narrow  nasal  floors  and  narrow  arches  by 
wide  floors. 

1  J.  Parsons  Schaeffer:  The  Sinus  Maxillaris  and  Its  Relations  in  the  Embryo,  Child,  and  Adult 
Man,  Amer.  Jour.  Anat.,  Vol.  10,  1910. 


76  THE  DEFINITIVE  NOSE 

It  is  obvious  from  a  study  of  a  sufficiently  large  series  of  specimens 
that  the  width  of  the  floor  of  the  nasal  fossa  is  more  dependent  upon  the 
size  of  the  maxillary  sinus  than  upon  the  degree  of  arching  of  the  palate, 
and  when  one  recalls  that  the  right  and  left  maxillary  sinuses  are  often 
very  asymmetrical  in  size,  the  difference  in  width  of  the  floors  of  the  two 
nasal  fossae,  is  more  comprehensible.  If  the  maxillary  sinus  is  small,  the 
nasal  fossa  near  its  floor,  e.g.,  the  meatus  inferior,  may  bulge  laterally 
over  the  alveolar  process  and  the  related  teeth.  The  reverse  may  also 
be  true  in  which  the  maxillary  sinus  hollows  out  beneath  the  inferior 
nasal  meatus  into  the  palatal  process  of  the  maxilla  (hard  palate,  floor 
of  nose)  to  form  the  palatal  recess  of  the  sinus  (Fig.  85).  These  anatom- 
ical variations  of  the  maxillary  sinuses  obviously  must  affect  the  width  of 
the  inferior  nasal  meatus,  e.g.,  the  floor  of  the  nasal  cavity,  regardless 
of  a  high  or  low  palatal  arch. 

The  floor  of  each  nasal  fossa  is  essentially  horizontal  in  the  sagittal 
plane,  however,  a  distinct  protuberance  is  present  just  inside  of  the  limen 
nasi,  over  which  an  instrument  must  be  passed  to  enter  the  inferior  nasal 
meatus  proper.  In  the  coronal  plane  the  floor  of  the  nasal  fossa  is  concave. 
Ventrally  the  floor  of  the  nasal  fossa  is  thick  and  robust,  this  gradually 
diminishing  to  a  very  thin  plate  at  the  junction  with  the  soft  palate. 

The  Nasopalatine  Canals. — Approximately  2  cm.  dorsal  to  the  inner 
margin  of  the  nostril  and  in  juxtaposition  to  the  nasal  septum  each  nasal 
fossa  presents  a  slight  depression  in  its  floor.  This  depression  leads  into 
a  small  canal  lined  with  mucosa,  prolonged  from  that  which  lines  the 
inferior  nasal  meatus.  This  funnel-shaped  tube  of  mucous  membrane,  the 
nasopalatine  canal  (canalis  incisivus,  canal  of  Stenson),  courses  obliquely 
caudalward  and  with  its  fellow  of  the  opposite  fossa  converges  toward 
the  nasal  septum,  descends  almost  vertically  and  passes  through  the 
Y-shaped  incisive  foramen  (foramen  incisivum,  anterior  palatine  canal) 
in  the  hard  palate.  The  right  and  left  nasopalatine  canals  may  join  and 
pass  through  the  stem  of  the  Y  incisive  foramen  as  a  common  channel, 
however,  more  commonly  each  retains  its  individuality.  The  canals  end 
on  the  roof  of  the  mouth  at  the  side  of  the  palatine  papilla  (papilla  palatina) 
or  incisive  pad  (Fig.  196). 

The  nasopalatine  canals  are  remnants  of  the  wide  communication 
between  the  nasal  and  oral  cavities  found  at  an  early  period  of  fetal  life. 

Occasionally  the  nasopalatine  canals  in  adult  man  lead  to  a  direct 
communication  between  the  nasal  fossae  and  the  buccal  cavity.  In 
the  vast  majority  of  instances,  however,  the  lumina  of  the  canals  are 
obliterated  and  represented  by  impervious  cords  of  epithelial  cells  con- 


NASAL  SEPTUM  77 

tinuous  with  the  epithelium  of  the  roof  of  the  mouth  at  one  extremity  and 
with  the  funnel-shaped  ciliated  epithelial-lined  depressions  in  the  floor 
of  the  nasal  fossae  at  the  other.  Indeed,  at  times  it  is  difficult  to  find 
any  remnant  of  the  canals  whatsoever.  The  obliteration  of  the  lumina 
often  begins  before  birth.  In  many  animals,  on  the  contrary,  the  naso- 
palatine  canals  remain  open  and  persist  as  such  throughout  life. 

Persistence  of  the  lumina  of  portions  of  the  nasopalatine  canals  may 
be  the  explanation  for  " cells"  in  the  maxillae  dorsal  to  the  upper  incisor 
teeth.  Indeed,  such  a  "cell"  could  communicate  with  either  the  inferior 
meatus  or  the  buccal  cavity;  or  in  the  event  that  both  extremities  of  the 
canals  became  impervious,  the  central  portion  (or  portions)  would  be  with- 
out a  drainage  channel  and  could  readily  become  cystic  (see  sinus  maxil- 
laris,  page  121). 

The  Roof  of  the  Nasal  Fossa. — The  roof  of  the  nasal  fossa  may  be 
considered  as  horizontal  and  wholly  formed  by  the  cribriform  plate  of  the 
ethmoid  bone.  It  may  also  be  considered  as  a  cranially  arched  structure, 
with  the  cribriform  plate  forming  the  horizontal  middle  portion;  the  body 
of  the  sphenoid  bone  together  with  the  wing  of  the  vomer  and  the  sphenoi- 
dal  process  of  the  palate  bone,  the  curved  dorsal  portion;  and  the  frontal 
and  nasal  bones,  the  curved  ventral  portion.  The  entire  framework  is 
covered  by  nasal  mucous  membrane. 

Ventrally  the  roof  of  the  fossa  is  very  narrow,  but  gradually  widens  as 
the  choanal  aperture  is  approached.  The  greatest  breadth  of  the  cribri- 
form plate  (roof  proper)  is  approximately  5  mm.  Ventrally  it  nar- 
rows and  allows  the  lateral  ethmoidal  masses  to  come  in  contact 
with  the  perpendicular  plate.  Cranially  the  cribriform  plate  supports 
the  olfactory  lobe  of  the  brain  and  is  perforated  by  foramina  for  the  pas- 
sage of  the  olfactory  nerves.  Ventrally  close  to  the  crista  galli  is  a  longitu- 
dinal fissure  (the  nasal  fissure)  for  the  transmission  of  the  anterior  eth- 
moidal branch  of  the  nasociliary  nerve  and  the  anterior  ethmoidal  vessels. 

The  Median  Wall  of  the  Nasal  Fossa,  e.g.,  The  Nasal  Septum  (septum 
nasi). — The  partition  between  the  right  and  left  nasal  fossae  is  formed: 
(i)  by  osseous  elements,  (2)  by  cartilaginous  elements,  and  (3)  by  integu- 
ment (Fig.  74). 

The  nasal  mucous  membrane  covers  all  portions  of  both  sides  of  the 
septum  save  the  vestibular  part  which  is  invested  by  integument  continued 
through  the  nares  from  the  surface  area.  It  is  smooth  and  more  or  less 
constant  in  thickness.  However,  the  more  extensive  glandular  and  vas- 
cular development  here  and  there  cause  the  mucosa  to  be  thrown  into 
relief  in  the  form  of  small  ridge-like  elevations  and  protuberances.  A 


78  THE  DEFINITIVE  NOSE 

fairly  constant  elevation  (the  tuberculum  septi)  is  found  on  the  septum  in 
juxtaposition  to  the  ventral  extremity  of  the  middle  nasal  concha.  More- 
over, oblique  mucosal  ridges  or  septal  plicae  (plicae  septi)  frequently  con- 
figure the  dorsocaudal  portion  of  the  septum.  These  folds  or  plicae, 
four  to  six  in  number,  are  placed  in  order  from  below  upward  and  forward 
and  have  as  their  precursors  the  mucosal  folds  which  appear  early  in 


FIG.   72. — Photograph  of  the  separate  bones  of  the  nasal  fossa,  etc. 

V   =  vomer;    /  =  frontal;     e   =  ethmoid;    5   =  sphenoid;     pal   =  palate;     Cni   =  concha    nasalis 
inferior;  m   =  maxilla;  I   =  lacrimal;  n    =  nasal;  /    =  temporal;   par   =  parietal. 

fetal  life  (see  page  37  and  Fig.  41).  They  usually  increase  in  size  up  to 
the  eighth  month  of  intrauterine  life,  then  undergo  regression  and  dis- 
appear early  in  infancy.  However,  occasionally  they  persist,  even  hyper- 
trophy into  tumor-like  obstructing  masses  in  the  adult  (see  page  261  for 
detailed  discussion  of  the  adult  nasal  mucous  membrane). 

(A)  The  osseous  portion  of  the  nasal  septum  (septum  nasi  osseum) 
is  formed  by  the  perpendicular  plate  of  the  ethmoid,  the  vomer,  the  frontal 


NASAL  SEPTUM  79 

(nasal)  spine  of  the  frontal,  the  rostrum  of  the  sphenoid  and  the  crests  of 
the  nasal,  maxillary  and  palate  bones. 

i.  The  vomer  is  a  thin,  irregularly  quadrilateral  bone  located  in  the 
dorsocaudal  portion  of  the  nasal  septum.  The  dorsal  border  of  the  bone 
projects  free  toward  the  nasopharynx  and  separates  the  choanae.  The 
inferior  border  articulates  with  the  nasal  crests  of  the  maxillary  and  palate 
bones.  The  superior  border,  the  thickest  part  of  the  bone,  is  divided  into 
two  spreading  alae  which  articulate  with  the  rostrum  of  the  body  of  the 


Probe  inductor  nasoFrorttaJis  »x 

Bulla  frantaUs ---^ 

Agger  nasi  fruH-oturbinal)  ^  s 

Proc.  -u,ncinatu&  SN 
ossis  eXJunaLcUilis   ^v»^ 

7J,7iclcfended    area  of 
-m^atus  nasi  mcdavs 

fossa.  Jtypophysws 


Siims  sjihenaidales  Proc.  ethjttoidcdis  Proc.  jnaxilletris 

(diuder ef,  siidster)       (concha   nasatts in£rjor\  fcoiicha  nasulis infbrhr\ 

FIG.  73. — The  osseous  lateral  nasal  wall  with  the  ethmoidal  conchae  or  turbinated  bones  removed. 
Note  the  undefended  area  of  the  meatus  nasi  medius  and  its  division  into  two  parts  (see  text,  page  92). 
Note  also  the  unusual  position  (frontal  plane)  of  the  osseous  septum  separating  the  right  and  left 
sphenoidal  sinuses  and  the  relations  of  the  hypophyseal  fossa. 

sphenoid  bone.  Moreover,  the  edge  of  each  ala  meets  the  vaginal  process 
of  the  sphenoid  and  the  sphenoidal  process  of  the  palate  bone.  The 
anterior  border  is  grooved  for  the  reception  of  the  septal  cartilage  and  in 
the  dorsocephalic  portion  is  ankylosed  on  one  or  both  sides  to  the  per- 
pendicular plate  of  the  ethmoid  bone.  Occasionally  the  septal  cartilage 
is  prolonged  tongue-like  between  the  vomer  and  the  perpendicular  plate 
of  the  ethmoid  in  the  formation  of  the  sphenoidal  process  of  the  septal 
cartilage  (Fig.  74).  The  ventral  extremity  of  the  vomer  forms  a  short 


8o 


THE  DEFINITIVE  NOSE 


vertical  border  which  abuts  the  incisive  crest  of  the  maxillae  dorsally  and 
is  extended  variously  at  its  upper  end  in  the  groove  of  the  crest.  More- 
over, the  lower  end  of  the  ventral  extremity  at  times  projects  between 
the  incisive  canals.  Rarely  the  vomer  shares  in  the  formation  of  the 
hard  palate  by  extending  between  the  palatine  processes  of  the  maxillae 
(see  development  of  vomer,  page  41). 

2.  The  mesethmoid  or  the  perpendicular  plate  (lamina  perpendicu- 
laris)  of  the  ethmoid  bone  represents  the  ossified  upper  portion  of  the 
primitive  cartilaginous  nasal  capsule.  It  forms  the  cephalic  third  of  the 
septum  of  the  nose,  articulating  with  the  frontal  (nasal)  spine  of  the  frontal 


r  .C.  ethmoidalis  posterior 
•  Sinus  5plicn.oida.lis  sinister 
Sinus  sphenoicUilis  dexter 


\    fcocessus  „, 

\        septi  cartilceyinei 

•  CartMau/o  vonuronasalis 

Cartilage  aJ,a.ris  ntajor 

FIG.   74. — A  dissection  showing  the  osseous  and  cartilaginous  septum  of  the  nose. 

bone  and  the  nasal  bones  ventrally,  with  the  septal  cartilage  and  the  vomer 
ventrally  and  caudally  (the  vomer  and  mesethmoid  may  be  joined  by 
osseous  tissue),  and  with  the  crest  of  the  sphenoid  dorsally.  The  cephalic 
border  of  the  mesethmoid  appears  in  the  cranial  cavity  above  the  cribri- 
form plate  as  the  crista  galli  and  in  doing  so  divides  the  roof  of  the  nasal 
cavity  into  two  halves. 

The  ventral  extension  of  the  mesethmoid  varies  considerably  and 
in  this  reciprocates  with  the  related  portion  of  the  septal  cartilage.  More- 
over, this  accounts  for  the  apparent  discrepancies  in  the  literature  con- 
cerning the  osseous  extent  of  the  nasal  septum.  Not  infrequently  the 


NASAL  SEPTUM  81 

mesethmoid  extends  as  far  as  the  caudal  or  distal  border  of  the  nasal 
bones.  Again  specimens  are  encountered  in  which  the  mesethmoid  is 
much  smaller,  terminating  ventrally  at  the  level  of  the  frontal  (nasal) 
spine  of  the  frontal  bone.  All  degrees  of  development  between  these 
two  extremes  are  found  in  a  series  of  specimens.  Obviously  the  septal 
cartilage  is  reciprocally  large  or  small  in  the  structural  formation  of  the 
nasal  septum.  The  variations  in  the  mesethmoid  must  have  a  consider- 
able bearing  in  connection  with  fractures  of  the  nose  and  septal  deviation. 
3.  The  remaining  osseous  septal  elements — the  frontal  (nasal)  spine 
of  the  frontal,  the  rostrum  of  the  sphenoid  and  the  crests* of  the  nasal, 


FIG.  75. — The  medial  or  nasal  wall  of  the  maxillary  sinus  exposed  from  the  sinus  side.  Note  the 
undefended  area  (4)  and  that  the  uncinate  process  does  not  articulate  with  the  inferior  nasal  concha. 
(Compare  with  Fig.  73.) 

i  =  ethmoid;  2  =  lacrimal;  3  =  uncinate  process  of  ethmoid;  4  =  mucous  membrane;  5  = 
palate  bone;  6  =  inferior  concha  or  turbinate;  7  =  maxilla. 

maxillary  and  palate  bones — serve  as  articulating  points  for  the  vomer, 
mesethmoid  and  septal  cartilage  and  thereby  participate  in  completing 
the  septal  margins  (Fig.  74). 

(B)  The  cartilaginous  portion  of  the  nasal  septum  (septum  nasi 
cartilagineum)  is  formed  by  the  septal  cartilage,  the  vomeronasal  carti- 
lages and  the  medial  crura  of  the  great  alar  cartilages. 

i.  The  cartilage  of  the  septum  (cartilage  septi  nasi)  is  irregularly 
quadrilateral  in  shape  and  completes  the  median  partition  ventrally  be- 


82  THE  DEFINITIVE  NOSE 

tween  the  right  and  left  nasal  fossae.  It  represents  the  ventral  extremity 
of  the  primordial  cartilaginous  cranium.  Its  dorsocephalic  border  is 
attached  to  the  perpendicular  plate  of  the  ethmoid  (mesethmoid) ;  its 
dorsocaudal  border  to  the  vomer  and  maxilla  (incisive  crest,  as  far  as  the 
anterior  nasal  spine).  Its  thick  ventrocephalic  border  is  fixed  along  the 
internasal  suture  above  and  below  it  becomes  confluent  with  the  lateral 
nasal  cartilages,  the  latter  extending  wing-like  from  it.  After  leaving 
the  position  of  the  lateral  cartilages,  the  ventrocephalic  border  of  the 
septal  cartilage  extends  between  the  greater  alar  cartilages  to  within  a 
half  inch  of  the  tip  of  the  nose,  the  medial  crura  of  the  great  alar  cartilages 
intervening  between  the  septal  cartilage  and  the  nasal  tip.  The  rotundity 
of  the  tip  of  the  nose  is  due  to  the  rounded  confluence  of  the  medial  and 
lateral  crura  of  the  greater  alar  cartilages. 

Dorsally  the  septal  cartilage  extends  variously  between  the  vomer 
and  the  perpendicular  lamina  of  the  ethmoid  (mesethmoid),  thus  form- 
ing the  so-called  sphenoidal  process  of  the  septal  cartilage  (processus  sphe- 
noidalis  septi  cartilaginei).  Indeed,  the  latter  may  be  sufficiently  elon- 
gated to  reach  the  sphenoid  bone— especially  in  children — and  very 
frequently  is  the  seat  of  a  ctista  or  ridge-like  horizontal  projection  into 
one  or  the  other  nasal  fossa,  causing  septal  asymmetry  (Fig.  74). 

2.  The  vomer onasal  cartilages  (cartilagines  vomeronasales)  are  two 
narrow  longitudinal  strips,  7  to  1 5  mm.  in  length,  which  lie  along  the  ventral 
portion  of  the  caudal  border  of  the  septal  cartilage.     In  this  position  the 
vomeronasal  cartilages  are  attached  to  the  vomer  dorsally  and  to  the 
maxilla  and  the  septal  cartilages  ventrally.     The  vomeronasal  cartilages 
are  not  always  differentiated  from  the  septal  cartilage  and  appear  as 
lateral  processes  from  its  caudal  border  (Fig.  74).     In  man  these  carti- 
lages reach   their  maximum   development  in  the  embryo.     They  are, 
however,  always  most  conspicuous  in  animals  in  which  the  vomeronasal 
organ  is  well  developed,  forming  a  protecting  and  supporting  framework 
for  the  organ.     It  is  doubtful  in  man  whether  the  diminutive  vomeronasal 
cartilages  have  anything  in  common  with  the  rudimentary  vomeronasal 
organ,  since  the  latter  is  always  located  in  the  septal  tissue  cephalic  to 
the  position  of  the  vomeronasal  cartilages  (Fig.  189).     Strictly  speaking, 
therefore,  one  should  not  say  that  the  latter  cartilages  are  supporting 
structures  for  the  vomeronasal  organ  (organ  of  Jacobson)  in  homo. 

3.  The  greater  alar  cartilage  or  cartilage  of  the  aperture  (cartilaginea 
alaris  major)  is  discussed  with  the  cartilages  of  the  external  nose  to  which 
the  reader  is  referred  (Figs.  68  and  69). 

(C)  The  membranous  portion  of  the  nasal  septum  (septum  nasi 


ASYMMETRY  OF  NASAL  SEPTUM  83 

membranaceum)  is  formed  by  the  medial  crura  of  the  great  alar  cartilages 
and  by  integument  and  subcutaneous  tela,  the  septal  cartilage  stopping 
short  of  it.  Owing  to  the  absence  of  the  latter  the  membranous  septum  is 
much  more  flexible  and  is  often  referred  to  as  the  septum  mobile  nasi 
(see  greater  alar  cartilage,  page  68,  Fig.  68). 

Asymmetry  of  the  Nasal  Septum. — During  fetal  life  and  in  infancy 
and  in  early  childhood,  the  nasal  septum  is  usually  symmetrical  and 
in  the  mid-sagittal  plane  throughout.  However,  the  author  has  seen 
asymmetrical  nasal  septa  in  individuals  of  the  early  childhood  period 
and  several  markedly  deviated  septa  in  fetuses.  Notwithstanding  these 
exceptions,  asymmetries  of  the  nasal  septum  usually  appear  after  the 
childhood  period,  the  majority  of  adults  presenting  asymmetries  varying 
from  slight  irregularities  to  deviations  which  completely  occlude  one  or 
the  other  nasal  fossa.  Indeed,  deflection  of  the  human  nasal  septum  is 
so  common  that  one  almost  thinks  of  it  as  normal  anatomy  in  spite  of 
the  fact  that  the  results  of  the  asymmetry  are  often  so  direful  that  surgical 
intervention  is  necessary.  One  must,  however,  bear  in  mind  that  a  goodly 
number  of  adults  have  essentially  symmetrical  septa  and  not  be  misled 
by  the  extravagant  statements  occasionally  made  that  straight  septa  are 
extremely  unusual. 

No  accurate  anatomical  classification  of  septal  asymmetries  can  be 
made  owing  to  the  divers  types  that  may  be  assumed.  The  asymmetry 
may  involve  all  the  constituents  of  the  septum  or  be  limited  to  the  septal 
cartilage  or  the  osseous  parts,  respectively.  Strangely,  the  dorsal  or 
free  border  of  the  nasal  septum  is  nearly  always  in  the  mid-sagittal  plane 
so  that  the  choanal  apertures  are  regularly  of  equal  size.  In  a  general  way, 
one  may  say  that  septal  asymmetry  is  due  to  septal  deflection  as  a  whole 
or  to  one  of  its  major  constituents,  or  to  spurs,  ridges,  etc.  Not  infre- 
quently the  latter  in  some  form  accompany  septal  deflection.  Often 
spurs  and  ridges  are  referred  to  as  septal  deflections  as  well. 

Very  common  seats  of  deflection  occur  along  the  articulation  between 
the  vomer  and  the  septal  cartilage,  and  the  articulation  between  the 
mesethmoid  and  the  vomer.  The  latter  articulation  is  particularly  vul- 
nerable when  the  sphenoidal  process  of  the  septal  cartilage  is  interposed 
for  a  goodly  distance  (Fig.  74).  At  these  articulations  angular  deflec- 
tions toward  one  or  both  sides  take  place  and  in  addition  may  give  rise 
to  ridge-like  folds  and  crests  or  to  more  localized  spurs.  It  must  be  re- 
membered, however,  that  the  septum  may  be  essentially  straight,  yet 
a  marked  ridge  or  spur  on  one  or  the  other  side  produce  an  asymmetry. 
Not  infrequently  one  or  the  other  of  the  septal  elements  is,  in  a  sense, 


84  THE  DEFINITIVE  NOSE 

dislocated.  A  very  characteristic  crest  (crista  lateralis)  frequently  devel- 
ops along  the  sphenoidal  process  of  the  septal  cartilage,  and  this  not  neces- 
sarily accompanying  septal  deviation  in  the  strict  sense.  Corresponding  to 
the  variable  degree  of  development  of  the  sphenoidal  process  of  the  septal 
cartilage  the  lateral  crista  extends  variously  along  the  lateral  aspect  of 
the  nasal  septum,  at  times  as  far  as  the  body  of  the  sphenoid  bone.  At 
times  the  entire  nasal  septum  forms  a  general  convexity  or  bulging  into 
one  nasal  fossa  with  a  reciprocal  concavity  and  enlargement  of  the  other 
fossa.  Again,  the. septum  may  deviate  in  a  double  or  S-shaped  manner, 
thereby  encroaching  simultaneously  upon  both  nasal  fossae. 

No  hypothesis  yet  formulated  seems  to  adequately  explain  the  occur- 
rence of  non-traumatic  asymmetry  and  deflection  of  the  nasal  septum 
in  all  cases.  Many  etiologic  theories  have  been  advanced  and  are  extant 
in  the  literature.  The  same  cause  cannot  be  equally  operative  in  all 
cases.  It  is  frequently  stated  that  non-traumatic  septal  deformity  is 
largely  a  product  of  ultra-civilization  and  that  it  is  unknown  among 
animals  and  savages  and  rare  in  all  semi-civilized  races.  The  studies  of 
Zuckerkandl  seem  to  confirm  this.  Moreover,  the  author  recently  ob- 
served in  a  mixed  series  of  skulls  that  the  greatest  percentage  of  septal 
deviation  was  found  in  the  skulls  of  Europeans,  which  is  in  accord  with 
Zuckerkandl's  tables. 

Apropos  of  the  latter  it  may  be  of  interest  to  mention  that  the  skull 
in  man,  as  in  all  mammals,  consists  of  two  parts — the  facial  part,  carrying 
the  teeth  and  developed  according  to  their  size,  and  the  brain  capsule, 
which  develops  in  accord  with  the  size  of  the  brain.  The  larger  the  brain, 
the  smaller  the  face  and  the  less  does  the  face  project  in  front  of  the  skull ; 
and,  on  the  contrary,  a  small  brain  means  a  larger  face  and  a  greater  facial 
projection  in  front  of  the  skull.  The  degree  of  facial  projection  from  the 
axis  of  the  skull  is  spoken  of  as  the  facial  angle,  which  is,  to  a  certain  degree, 
an  index  of  brain  development.  The  facial  angle  is  smallest  in  the  ultra- 
civilized  races  of  man,  considerably  larger  in  the  lower  races,  and  larger 
still  in  the  anthropoids.  This  means  that  the  degree  of  flexion  (angle  of 
flexion)  of  the  cranial  axis  (basion  to  nasion  line)  is  greatest  in  the  highly 
civilized  races  and  lessens  as  one  passes  from  the  lower  races  to  the  an- 
thropoids. Moreover,  the  nasal  septum  is  seemingly  encroached  upon 
more  and  more  by  the  forward  cranial  extension  incident  to  brain  growth 
as  one  passes  from  the  anthropoids  to  the  ultra-civilized  races  of  man. 
The  problem,  of  course,  is  whether  or  not  there  is  a  balanced  adjustment 
of  all  parts  of  the  cranium  and  face  in  this  evolution.  If  there  is,  the  grad- 
ual alteration  of  the  facial  angle  cannot  be  a  factor  in  septal  asymmetry. 


ASYMMETRY  OF  NASAL  SEPTUM  85 

On  the  other  hand,  if  all  parts  do  not  develop  in  accord  with  the  changes 
incident  to  the  lessening  of  the  facial  angle,  one  readily  sees  that  the  "fixed" 
position  of  the  nasal  septum  might  be  encroached  upon  and  the  septum 
correspondingly  deformed. 

In  studying  the  nasal  septum  one  is  impressed  with  its  anatomical 
situation.  Located  as  it  is  between  the  unyielding  frontal  and  ethmoid 
bones  above  and  the  sphenoid  bone  behind  and  the  hard  palate  below, 
the  septum  is  essentially  fixed  in  position.  Any  increase  in  its  cephalo- 
caudal  (vertical)  diameter  must  necessarily  lead  to  a  buckling  of  the  sep- 
tum as  a  whole  or  to  a  deviation  of  one  of  its  component  elements.  It 
is  not  clear  what  would  cause  the  septum  to  outgrow  the  region  set  for 
it.  Possibly  a  remote  and  slight  trauma  may  have  altered  the  balanced 
nutrition  and  in  consequence  cause  one  or  more  of  the  septal  elements  to 
outgrow  its  region.  The  vomer  especially  seems  to  be  at  fault  owing 
to  increased  development  in  the  vertical  plane.  Ossification  along  the 
line  of  union  between  the  mesethmoid  and  the  vomer  is  often  excessive 
and  doubtless  is  an  important  factor  in  the  deviation  of  the  septum  in 
its  ventral  two- thirds.  Should  the  cranial  and  facial  bones  grow  at  the 
expense  of  the  nasal  septum  the  reverse  condition  would  prevail,  namely— 
a  deviated  septum  owing  to  encroachment  upon  its  area. 

Not  infrequently  one  finds  enlarged  nasal  conchae  and  enlargement 
of  the  entire  ethmoidal  labyrinth  as  the  obvious  causes  of  septal  deviation 
(Fig.  161). 

Great  importance  is  given  by  Trendelenburg  and  Freeman  to  a  per- 
sistent high  or  Gothic  arch  of  the  hard  palate  as  a  causative  factor  of  a 
deflected  nasal  septum.  This  condition  would  seemingly  lead  to  encroach- 
ment upon  the  vomer  and  the  mesethmoid  and  cause  them  to  buckle. 
However,  when  one  finds  markedly  deviated  septa  in  extremely  flat 
palatal  arches  he  questions  the  Gothic  arch  as  a  factor. 

Jarvis  and  others  strongly  support  the  theory  of  heredity;  while 
Talbot  believes  that  deflected  septa  are  "stigmata  of  degeneracy"  in  all 
cases  where  traumatism  is  not  a  factor.  Incoordination  or  unbalanced 
development  in  the  growth  of  the  skeleton  of  the  nose  and  face  doubt- 
less account  for  many  deflected  septa.  Presumably  this  is  the  thought 
Dr.  Talbot  wishes  to  convey. 

Traumatism,  often  remote  and  trivial,  is  according  to  many  investi- 
gators, the  most  frequent  cause  of  septal  asymmetry  (Bosworth).  The 
author  was  impressed  recently  in  an  examination  of  a  large  series  of  skulls 
of  the  relative  frequency  of  some  evidence  of  a  previous  trauma  to  the 
bridge  of  the  nose.  The  architecture  of  the  framework  of  the  nose  is 


86  THE  DEFINITIVE  NOSE 

such  that  trauma  inflicted  to  the  nasal  bridge  readily  influences  the 
cartilaginous  portion  of  the  nasal  septum.  Despite  the  elasticity  and 
pliability  of  the  nose  of  the  child  at  term  trauma  inflicted  during  birth 
may  be  the  underlying  factor  in  dislocation  of  the  ventral  portion  of  the  nasal 
septum  from  the  depression  formed  by  the  crest  of  the  intermaxillary  bone. 
Indeed,  Kyle  believes  "  that  many  cases  of  the  so-called  congenital  deformity 
in  the  bones  of  the  nose  are  due  to  the  fact  that  at  birth  during  labor, 
owing  to  the  position  of  the  head  in  the  birth  canal,  considerable  pressure 
has  been  exerted  on  the  soft,  almost  cartilaginous,  bones  of  the  nose.  It 
is  well  known  that  much  can  be  done  toward  the  shaping  of  the  nose  at 
this  time."  Ballenger,  while  believing  that  trauma  is  a  factor  in  a  certain 
number  of  cases  does  not  believe  that  it  explains  a  majority  or  even  a 
large  percentage  of  deflected  septa.  He  feels  that  Talbot  strikes  at  the 
"root  of  the  matter."1  Kurd2  likewise  believes  that  "deviation  of  the 
septum,  which  is  sometimes  traumatic,  is  usually  due  to  unequal  develop- 
ment of  the  bony  frame  of  the  face."  It  would,  therefore,  appear  estab- 
lished that  asymmetries  in  development  and  trauma,  the  latter  not  infre- 
quently unrecognized  at  the  time,  are  the  most  frequent  and  important 
etiological  factors  in  septal  deformity. 

Apparently  rickets  and  septal  asymmetry  co-exist,  as  do  also  septal 
asymmetry,  high-arched  palate  and  nasopharyngeal  obstruction.  The 
inter-relations  of  these  conditions,  however,  need  further  investigation 
before  any  conclusions  of  value  can  be  given. 

Perforation  of  the  Nasal  Septum. — Congenital  perforation  of  the 
nasal  septum  is  apparently  a  rare  condition.  In  a  large  series  of  specimens 
(well  over  300)  the  author  found  two  instances  of  congenital  perforation, 
both  of  which  occurred  in  infantile  heads. 

The  vast  majority  of  perforations  of  the  nasal  septum  are  due  to 
disease:  syphilis,  tuberculosis,  acute  infectious  diseases  (diphtheria,  scarlet 
fever,  typhoid  fever).  Ballenger3  thinks  that  atrophic  or  perforating 
ulcer  of  the  septum  is  probably  the  most  common  type  of  perforation. 
It  is  well  known  that  septal  perforation  has  followed  surgical  procedures, 
moreover,  that  the  persistent  use  of  the  patient's  finger  in  attempting  to 
remove  crusts  from  the  cartilaginous  part  of  the  septum  has  ultimately 
led  to  septal  perforation. 

The  Lateral  Wall  of  the  Nasal  Fossa.— The  lateral  nasal  wall  is  divided 
into  two  unequal  portions  by  the  limen  nasi — a  small  ventral  and  caudal 

1  Ballenger:  Diseases  of  the  Nose,  Throat  and  Ear,  Philadelphia,  1914. 

2  Binney's  Treatise  of  Regional  Surgery. 

3  Loc.  cit. 


LATERAL  WALL  OF  NASAL  FOSSA 

portion  corresponding  to  the  lateral  wall  of  the  nasal  vestibule  and  a 
larger  dorsal  portion  representing  the  lateral  wall  of  the  nasal  fossa  proper. 
It  is  the  latter,  the  most  complex  of  the  boundaries  of  the  nasal  fossa, 
that  concerns  us  in  this  connection.  The  wall  is  characteristically  con- 
figured by  the  projecting  and  operculating  major  and  minor  (accessory) 
nasal  conchae  or  turbinates  and  by  the  resultant  nasal  meatuses  and 
secondary  furrows.  Moreover,  the  paranasal  (accessory)  sinuses,  develop- 
mentally  outgrowths  of  the  nasal  mucous  membrane,  by  their  ostia  and 
nasal  expansion,  variously  mold  the  lateral  wall.  Indeed,  the  ethmoidal 
cells  may  so  throw  the  lateral  wall  into  relief  at  places  that  thesnasal  fossa 
is  reduced  to  a  mere  potential  cleft. 

The  osseous  framework1  of  the  lateral  wall  is  formed  vkntrally, 
from  above  downward,  by  the  deep  surface  of  the  nasal  bone  ajnd  the 
medial  surfaces  of  the  frontal  process  and  body  of  the  maxilla;  centrally, 
from  above  downward,  by  the  medial  wall  of  the  ethmoidal  labyrinth  and 
its  conchal  appendages,  the  lacrimal  bone,  the  inferior  nasal  concha  and 
the  medial  surface  of  the  body  of  the  maxilla;  dor  sally,  by /the  medial 
surface  of  the  perpendicular  plate  of  the  palate  bone  and  ph^ryngealward 
by  the  medial  surface  of  the  medial  lamina  of  the  pterygoid  process  of  the 
spllenoidjbone  (Fig.  72). 

The  obionglabyfinth  or  lateral  mass  of  the  ethmoid  bone  is  suspended 
from  the  nasal  surface  of  the  lateral  portion  of  the  horizontally  placed 
cribriform  plate  and,  in  addition  to  enclosing  numerous  irregularly  shaped 
spaces  (cellulae  ethmoidales),  gives  rise  to  scroll-like  masses  of  overhanging 
turbinated  bones  (conchae  ethmoidales).  Divergent  opinions  are  held 
regarding  the  number  of  such  bones  that  constitute  the  typical  ethmoidal 
field  in  post-fetal  life.  In  a  study  of  264  lateral  nasal  walls,  the  writer 
found  1 60  with  three  ethmoidal  conchae,  98  with  two,  4  with  four,  and  2 
with  one.  From  this  examination  it  would  appear  that  three  ethmotur- 
binals  (conchae  nasales  media,  superior,  et  suprema  I)  should  be  considered 
as  the  typical  ethmoidal  field  rather  than  two  as  is  usually  stated  (Fig. 
146).  However,  it  would  be  better  to  consider  both  fields  (two  and  three 
ethmoidal  conchae)  as  normal  anatomic  types  since  they  occur  so  fre- 
quently. Departures  from  these  are  relatively  few  and  unimportant 
(see  embryology,  Chapter  I).  Moreover,  the  independent  maxilloturbi- 
nal,  the  concha  nasalis  inferior,  projects  from  the  caudal  portion  of  the 
bony  lateral  wall  and  is  similarly  overhanging  in  character.  The  naso- 
turbinal  (agger  nasi)  is  extremely  rudimentary  in  man  and  courses  parallel 
to  the  dorsum  of  the  nose. 

1  Osteological  details  of  individual  bones  are  omitted. 


88  THE  DEFINITIVE  NOSE 

The  several  nasal  conchae  together  with  the  floor  of  the  nasal  fossa 
form  ventrodorsally-directed  oblong  fossa — the  meatus  nasi  inferior, 
media,  superior,  et  suprema  I.  The  conchae  are  always  located  cephalic 
to  the  corresponding  meatuses  which  with  the  contained  structures  they 
partially  operculate.  Lateralward  from  the  nasal  septum  and  medial- 
ward  from  the  projecting  and  overhanging  nasal  conchae  remains  a  cleft- 
shaped  space  which  extends  from  the  nasal  floor  to  the  nasal  roof — the 
common  nasal  meatus  (meatus  nasi  communis),  into  which  the  nasal 
meatuses  proper  open.  Dorsally  the  nasal  meatuses  open  into  the  naso- 
pharyngeal  meatus  (meatus  nasopharyngeus)  which  in  turn  communi- 
cates with  the  choana  (posterior  naris)  and  the  nasopharynx. 

Immediately  beyond  the  vestibule  the  bony  nasal  fossa  rapidly 
expands  into  the  nasal  atrium  (atrium  nasi,  atrium  meatus  medii).  This 
expansion  is  wholly  due  to  a  saucer-like  depression  in  the  lateral  nasal 
wall  in  advance  of  the  entrance  into  the  middle  nasal  meatus.  Ventrally 
and  cephalically  the  nasal  atrium  is  limited  by  the  agger  nasi,  a  rudi- 
mentary nasoturbinal  which  in  many  mammals,  e.g.,  the  sheep,  dog,  pig, 
etc.,  attains  a  very  large  size.  Ventral  to  the  agger  nasi  and  limited  by 
the  ental  surface  of  the  dorsum  of  the  nose  and  extending  from  the  nasal 
aperture  to  the  roof  of  the  nose  is  a  cleft-like  passage — the  nasal  carina 
of  Meckel  (carina  nasi  Meckelii),  the  olfactory  sulcus  (sulcus  olfactorius). 

Over  the  entire  irregular  osseous  skeleton  of  the  lateral  nasal  wall  is 
stretched  the  nasal  mucous  membrane ;  moreover,  is  continued  through  the 
various  ostia  into  the  paranasal  sinuses  and  becomes  continuous  with  the 
mucosa  of  the  nasolacrimal  duct.  In  addition  to  covering  the  osseous 
framework,  the  mucous  membrane  bridges  over  dehiscences  in  the  lateral 
bony  wall  of  the  middle  meatus  and  the  median  wall  of  the  maxillary 
sinus  (see  mucous  membrane,  page  261,  and  base  or  median  wall  of  maxil- 
lary sinus,  page  in). 

The  inferior  nasal  concha  (concha  nasalis  inferior,  maxilloturbinal) 
is  an  independent,  slender,  scroll-like  lamina  of  bone  developed  by  ossifi- 
cation in  the  infolded  caudal  border  of  the  lateral  plate  of  the  cartilaginous 
nasal  capsule.  It  articulates  by  its  attached  border  with  the  turbinate 
crest  (crista  conchalis)  of  the  maxilla,  then  ascends  sharply,  forms  the 
lacrimal  process  (processus  lacrimalis)  which  completes  the  osseous 
nasolacrimal  canal  and  articulates  with  the  lacrimal  bone.  Farther 
dorsad  the  attached  border  is  folded  caudalward  in  the  maxillary  process 
(processus  maxillaris)  which  aids  in  closing  the  bony  hiatus  of  the  maxillary 
sinus,  and  by  its  convex  imbricated  border  overlaps  the  margin  of  the 
maxillary  hiatus  and  articulates  with  the  palate  bone  dorsally.  A  variable 


LATERAL  WALL  OF  NASAL  FOSSA  89 

projection  (the  processus  ethmoidalis)  extends  from  the  dorsosuperior 
portion  of  the  attached  border  of  the  inferior  concha  to  articulate  with 
the  uncinate  process  of  the  ethmoid  across  the  maxillary  hiatus  and  with 
the  conchal  crista  (crista  conchalis)  of  the  palate  bone  behind.  The  thick- 
ened caudal  or  free  border  is  laterally  curled  upon  itself  and  at  times  con- 
tains one  or  more  incisurae,  giving  rise  to  bi-  or  tri-lobed  forms  of  the  in- 
ferior nasal  concha.  The  lateral  surface  is  concave,  the  medial  convex. 
The  longitudinal  ridge  on  the  medial  surface  may  represent  (in  a  rudi- 
mentary form)  the  upper  curled  plate  seen  in  the  gibbon.  The  elongated 
dorsal  extremity  of  the  inferior  concha  is  sharp  and  pointed,  the  mucosa 
giving  it  a  blunt  and  rounded  appearance  in  the  recent  and  living  state. 
The  ventral  extremity  is  flat,  broad  and  edged  and  with  the  overlying 
mucosa  merges  gently  with  the  lateral  wall.  The  concha  is  covered  by  a 
thick  mucous  membrane  which  contains  in  its  tela  submucosa  numerous 
venous  plexuses  which  assume  the  character  and  role  of  an  erectile  tissue — 
plexus  cavernosi  concharum  (Fig.  183).  The  mucosa-covered  lamella 
of  bone  extends  from  a  field  some  distance  behind  the  limen  nasi  to  a 
point  from  10  to  12  mm.  in  advance  of  the  choana,  and  in  its  course 
overhangs  the  inferior  nasal  meatus  and  the  contained  ostium  of  the 
nasolacrimal  duct.  In  the  recent  state  the  attached  border  of  the  inferior 
concha  is  distinctly  arched  in  the  ventrodorsal  plane. 

The  inferior  nasal  meatus  (meatus  nasi  inferior)  is  of  considerable 
size,  being  limited  by  the  arched  attached  border  of  the  inferior  nasal 
concha  cephalically,  by  the  nasal  floor  caudally,  and  by  the  nasal  septum 
and  the  lateral  nasal  wall  medially  and  laterally,  respectively.  It  measures 
from  4.5  to  5.8  cm.  in  length,  beginning  variously  from  2.5  to  3.7  cm. 
dorsal  to  the  tip  of  the  nose.  As  mentioned  previously  in  connection 
with  the  floor  of  the  nose,  the  inferior  nasal  meatus  is  narrow  at  its  ventral 
extremity,  however  rapidly  expanding  in  width  and  height  and  again 
gradually  narrowing  as  the  choanal  extremity  is  reached. 

The  ostium  of  the  nasolacrimal  duct  (ostium  nasolacrimale)  is 
variously  located  on  the  ventral  portion  of  the  lateral  wall  of  the  inferior 
nasal  meatus.  Its  position  varies  from  15  to  20  mm.  dorsal  to  the  limen 
nasi  and  from  30  to  40  mm.  dorsal  to  the  naris  (anterior  naris).  Moreover, 
its  location  in  the  cephalocaudal  plane  varies  likewise.  It  is  frequently 
found  in  the  extreme  cephalic  portion  (apex  of  dome)  of  the  inferior  meatus 
immediately  caudal  to  the  attachment  of  the  inferior  nasal  concha  to  the 
lateral  nasal  wall.  Again,  the  lacrimal  ostium  may  be  10  mm.  caudal  to 
the  above  point.  Between  these  two  extremes  ostia  are  found  at  various 
levels.  The  ostium  nasolacrimale  is  usually  a  single  opening,  however, 


go  THE  DEFINITIVE  NOSE 

duplication  and  triplication  occur  (see  embryology,  pages  50  and  51,  and 
Fig.  177). 

The  unqualified  statement  found  in  many  text-books  that  the  ductus 
nasolacrimalis  at  the  point  of  communication  with  the  inferior  nasal 
meatus  is  provided  with  a  mucous-membrane  valve  (plica  lacrimalis  or  the 
so-called  valve  of  Hasner)  is  at  variance  in  very  many  instances  with  the 
real  anatomic  condition.  A  study  of  the  ostium  nasolacrimale  in  a  large 
series  of  cadavers  demonstrated  to  the  author  that  there  is  no  unvarying 
typical  form,  rather  several  normal  anatomic  types.  The  ostium  may  pass 
through  the  nasal  mucosa  obliquely,  be  slit-like  and  indefinite,  and  essen- 
tially a  potential  cleft  guarded  by  a  mucosal  flap.  Again  the  ostium  may 
pass  through  the  nasal  mucosa  directly  and  be  surrounded  by  osseous  walls, 
thus  causing  it  to  stand  permanently  open  as  a  wide  mouth,  immediately 
caudal  to  the  junction-point  of  the  attached  border  of  the  inferior  concha 
and  the  lateral  nasal  wall.  Ostia  in  the  latter  position  are  never  guarded 
by  valves  or  mucosal  flaps  and  are  easily  located  and  probed.  Another 
common  type  of  ostium  is  one  in  which,  extending  from  the  aperture 
proper,  is  a  fairly  deep,  gutter-like  groove.  The  latter  may  become 
shallower  and  shallower  as  the  floor  of  the  nose  is  approached,  or  become 
deeper,  ultimately  ending  as  a  blind  pouch.  Nipple-like  mucosal  pro- 
jections on  the  lateral  wall  of  the  inferior  meatus,  surmounted  by  the 
ostium  nasolacrimale,  are  likewise  encountered.  Minor  departures  from 
these  types  are  common,  but  unimportant  (see  Fig.  177  for  types). 

The  middle  nasal  concha  (concha  nasalis  media)  is  relatively  large. 
Hanging  valve-like  over  the  middle  nasal  meatus  it  hides  or  operculates  a 
number  of  minor  or  secondary  conchae  and  furrows  and  a  variable  number 
of  anterior  ethmoidal  cells.  The  skeleton  of  the  middle  concha  is  not  an 
independent  osseous  element,  but  an  appendage  of  the  lateral  ethmoidal 
mass.  Over  it  is  stretched  a  thick  mucous  membrane  rich  in  venous 
networks  that  assume  the  character  of  an  erectile  tissue  similar  to  that 
of  the  inferior  concha.  The  heavy  mucosa  gives  the  middle  concha  a 
robust  appearance  (Fig.  159). 

The  free  border  of  the  middle  concha  in  the  recent  state  is  from  40  to 
50  mm.  long.  It  usually  presents  a  marked  genu,  giving  rise  to  a  short 
ventral  vertical  limb  and  a  longer  dorsal  horizontal  limb.  Occasionally 
little,  if  any,  angulation  occurs.  Not  infrequently  the  middle  concha 
undergoes  enlargement  at  the  genu  in  the  formation  of  a  distinct  lobule. 
Moreover,  a  secondary  nodule  often  develops  on  the  free  surface  of  the 
lobule.  Both  the  lobule  and  nodule  are  better  developed  relatively  in  the 
fetus  and  newborn  than  in  the  adult  (see  page  25  and  Figs.  19  and 


LATERAL  WALL  OF  NASAL  FOSSA  91 

30).  It  seems  established  that  the  lobule  and  secondary  nodule  of  the 
human  ethmoidal  conchae  (particularly  well  developed  in  the  middle) 
are  the  homologues  of  the  sharp  ventral  projection  of  the  ethmotur- 
binals  of  mammals.  Occasionally  the  lobule  of  the  middle  concha 
assumes  large  dimensions  and  mechanically  obstructs  the  middle  meatus 
at  this  point.  Indeed,  the  mass  may  crowd  the  nasal  septum  toward 
the  opposite  side.  These  lobules  must  not  be  confused  with  enlargements 
due  to  ethmoidal  (conchal)  cells  (see  page  221  and  Figs.  159,  160  and 
161). 

The  attached  border  of  the  middle  concha  ascends  ventrally  on 
the  surface  of  the  lateral  ethmoidal  mass  to  near  the  roof  of  the  nasal 
fossa  and  from  here  it  curves  caudally  and  dorsally  to  terminate  below  the 
junction-point  of  the  ventral  and  caudal  surfaces  of  the  body  of  the  sphe- 
noid bone  at  the  posterior  nasal  sulcus.  The  ascending  limb  of  the 
attached  border  in  the  recent  state  is  inconstant  in  its  extent  owing  to 
the  variability  in  development  of  the  ascending  limb  of  the  superior 
meatus. 

The  lateral  surface  of  the  middle  concha  is  not  infrequently  distinctly 
concave  in  frontal  section  owing  to  a  lateral  and  cephalic  curling  of  its 
free  border.  Indeed,  the  curling  may  be  so  marked  that  a  pseudo  para- 
nasal  sinus  is  formed  with  a  slit-like  aperture  on  the  lateral  surface  of  the 
concha.  Such  sinus-like  inclusions  must  not  be  confused  with  true 
paranasal  sinuses  often  found  in  the  middle  concha  (see  page  226). 

The  medial  surface  of  the  middle  concha  frequently  presents  second- 
ary furrows,  best  marked  in  the  newborn  child.  Single  and  deeply  cut 
furrows  partially  divide  the  middle  concha  into  superior  and  inferior 
portions,  the  former  often  erroneously  considered  the  superior  nasal  concha 
(see  page  26).  Occasionally  the  superior  surface  of  the  middle  concha  near 
the  attached  border  gives  rise  to  a  ridge-like  elevation  (crista  suprema, 
Killian)  which  passively  deepens  the  inferior  recess  of  the  superior  nasal 
meatus  (see  page  35  and  Fig.  34). 

The  middle  nasal  meatus  (meatus  nasi  medius)  is  the  most  im- 
portant and  complex  of  the  nasal  meatuses,  and  is  developmentally 
and  topographically  divided  into  ascending  and  descending  rami.  The 
latter  is  spacious  and  arched,  conforming  to  the  contour  of  the  middle 
and  inferior  nasal  conchae;  the  former  much  less  roomy  and  in  a  sense 
a  mere  extension  toward  the  frontal  region  of  the  descending  ramus  or 
middle  meatus  proper.  Moreover,  the  middle  meatus  is  largely  overhung, 
and  its  contained  structures — the  minor  or  accessory  nasal  conchae  and 
meatuses  and  portions  of  the  ethmoidal  cells,  together  with  the  ostia  of 


92  THE  DEFINITIVE  NOSE 

the  latter  and  those  of  the  frontal  and  maxillary  sinuses — are  hidden  from 
view  by  the  valve-like  operculating  character  of  the  middle  nasal  concha. 
Indeed,  it  is  necessary  to  entirely  ablate  the  middle  concha  in  order  to 
expose  the  middle  nasal  meatus  for  a  detailed  study  (Figs.  153  and 

197)- 

At  this  juncture  it  is  essential  to  recall  that  in  the  fetus,  minor  or 
accessory  nasal  conchae  or  folds  with  resulting  secondary  meatuses  or 
furrows  are  formed  on  the  lateral  wall  of  both  the  ascending  and  descending 
rami  of  the  middle  nasal  meatus  (see  page  27).  Some  of  these  persist, 
others  lose  their  identity  as  such  by  merging  into  one,  and  some  disappear 
altogether  (Figs.  25  and  33).  In  the  descending  ramus  of  the  middle 
meatus  are  developed  from  the  early  secondary  folds  and  furrows  the 
definitive  ethmoidal  bulla  (bulla  ethmoidalis),  the  uncinate  process  (pro- 
cessus  uncinatus),  the  suprabullar  furrow,  and  the  ethmoidal  infundibulum 
(infundibulum  ethmoidale).  Occasionally  a  furrow — a  persistent  em- 
bryonic bullar  furrow,  is  formed  on  the  lateral  aspect  of  the  ethmoidal 
bulla.  Moreover,  the  accessory  furrows  contain  ostia  of  paranasal  sinuses. 
In  the  ascending  ramus  (the  frontal  recess)  of  the  post-pubertal  nose  are 
found  remnants  of  fetal  frontal  or  accessory  conchae  and  furrows  in  the 
form  of  low  ridges  separating  variously  anterior  ethmoidal  cells  and  the 
ostia  of  such  cells.  Moreover,  the  frontal  sinus  bears  a  varied  relation  to 
these  regressed  folds  and  furrows. 

The  lateral  wall  of  the  descending  ramus  of  the  middle  meatus 
between  the  caudoventral  border  of  the  uncinate  process  and  the  inferior 
concha,  between  the  dorsal  extremity  of  the  uncinate  process  and  the 
perpendicular  plate  of  the  palate  bone,  and  between  the  dorsal  extremity 
of  the  uncinate  process  and  the  ethmoidal  bulla  may  be  termed  the  un- 
defended C-shaped  region  of  the  lateral  nasal  wall.  Here  the  mucous 
membranes  of  the  nasal  fossa  and  the  maxillary  sinus  come  into  actual 
contact  with  each  other,  there  being  no  intervening  osseous  skeleton  as 
elsewhere.  Moreover,  it  is  in  this  region  that  the  accessory  ostium  of  the 
maxillary  sinus  (ostium  maxillare  accessorium)  is  variously  established 
(see  page  130  and  Figs.  75  and  145).  Very  frequently  the  C-shaped 
membranous  space  is  broken  into  two  portions  by  the  articulation  of  the 
caudally  directed  root  of  the  uncinate  process  with  the  ethmoidal  process 
of  the  inferior  nasal  concha  (Fig.  73). 

The  ethmoidal  infundibulum  (infundibulum  ethmoidate)  is  the  deep 
crescentic  groove  or  secondary  meatus  coursing  along  the  lateral  wall  of 
the  descending  ramus  of  the  middle  nasal  meatus.  It  is  bounded  cephal- 
ically  and  laterally  by  the  ethmoidal  bulla,  certain  anterior  ethmoidal 


LATERAL  WALL  OF  NASAL  FOSSA  93 

cells  and  the  undefended  mucous  membrane,  and  caudally  and  medially 
by  the  uncinate  process.  At  its  ventral  and  cephalic  extremity  the 
ethmoidal  infundibulum  usually  ends  blindly  with  or  without  dilatation 
by  forming  an  anterior  ethmoidal  cell  (Figs.  124  and  125).  Moreover, 
it  occasionally  terminates  in  direct  continuity  with  -the  nasofrontal  duct 
(infundibulum  of  frontal  sinus)  or  the  frontal  sinus  when  the  duct  is 
wanting  (Fig.  127).  The  ethmoidal  infundibulum  either  ends  blindly 
dorsocaudally  (posteriorly)  in  a  pocket,  due  to  a  prominent  cephal- 
ically  arched  lamina  of  the  uncinate  process,  or  it  ends  by  gradually 
becoming  shallower  and  shallower,  ultimately  losing  its  identity  in 
the  middle  nasal  meatus — the  latter  when  the  upturned  lamina  of  the 
uncinate  process  fails  to  develop  sufficiently  to  form  a  ledge  over  which 
the  mucous  membrane  must  course  in  the  formation  of  a  pocket  (Figs. 
73  and  127). 

The  ethmoidal  infundibulum  is  in  communication  with  the  middle 
nasal  meatus  by  way  of  a  cleft-like  aperture — the  semilunar  hiatus 
(hiatus  semilunaris),  located  between  the  free  border  of  the  uncinate 
process  and  the  ethmoidal  bulla.  The  semilunar  hiatus  is  from  15  to 
20  mm.  long  and  varies  considerably  in  width,  owing  largely  to  the  vari- 
ability in  size  of  the  ethmoidal  bulla.  Indeed,  the  bulla  may  be  of  such 
size  as  to  come  in  contact  with  the  free  border  of  the  uncinate  process, 
in  which  case  the  semilunar  hiatus  is  merely  a  potential  cleft  (Fig.  161). 
The  semilunar  hiatus  extends  to  the  frontal  recess  and  there  establishes 
various  relationships  with  anterior  ethmoidal  cells  and  the  nasal  part  of 
the  frontal  sinus  (see  page  160). 

The  ethmoidal  infundibulum  is  wider  near  its  floor  than  it  is  at  its 
semilunar  hiatus.  Moreover,  it  gradually  becomes  wider  as  its  dorssl 
extremity  is  neared.  The  depth,  e.g.,  the  distance  from  the  free  border 
of  the  uncinate  process  to  the  floor,  varies  from  i  to  12  mm., with  an  ap~ 
proximate  average  of  5  mm.  Near  its  dorsal  extremity  and  either  in  its 
lateral  wall  near  the  floor  or  in  its  floor,  the  ethmoidal  infundibulum  con- 
tains the  ostium  of  the  maxillary  sinus  (ostium  maxillare,  page  127). 
At  this  point  the  infundibulum  is  usually  at  its  maximum  width.  More- 
over, the  ostia  of  certain  anterior  ethmoidal  cells  (infundibular  cells)  are 
variously  located  in  the  ventral  half  of  the  ethmoidal  infundibulum  (Figs. 
159  and  197). 

The  uncinate  process  (processus  uncinatus)  is  a  long,  thin  accessory 
concha  which  projects  from  the  ventral  portion  of  the  lateral  ethmoidal 
mass  or  labyrinth  under  cover  of  the  lacrimal  bone.  It  courses  or  curves 
dorsalward,  caudalward,  and  lateralward  under  cover  of  the  middle 


94  THE  DEFINITIVE  NOSE 

nasal  concha  in  the  lateral  wall  of  the  middle  meatus,  and  in  the  articu- 
lated skull  lies  across  the  hiatus  of  the  maxillary  sinus,  forming  part  of 
the  medial  or  nasal  wall  of  that  cavity.  The  uncinate  process  at  its 
dorsal  and  free  extremity  usually  terminates  by  forming  two  roots:  One, 
fairly  constant,  is  made  up  of  one  or  more  irregular,  caudally-directed 
projections  for  articulation  with  the  ethmoidal  process  of  the  inferior 
nasal  concha;  the  other,  less  constant,  curves  cephalically  behind  the 
dorsal  extremity  of  the  ethmoidal  infundibulum  and  when  prominent 
causes  the  latter  in  the  recent  state  to  terminate  in  a  deep  pocket  just 
dorsal  to  the  ostium  of  the  maxillary  sinus.  This  pocket  is  significant 
since  it  is  so  located  that  it  will  direct  any  fluid  coming  to  the  dorsal 
extremity  of  the  infundibulum  ethmoidale  through  the  ostium  maxillare 
into  the  sinus  maxillaris.  The  uncinate  process  with  its  covering  of  thin 
mucous  membrane  forms  the  caudomedial  boundary  of  the  ethmoidal 
infundibulum  and  by  its  free  edge  the  caudal  boundary  of  the  semilunar 
hiatus.  It  varies  in  breadth  in  the  recent  state  from  i  to  12  mm.,  thereby 
affecting  the  depth  and  the  efficiency  as  a  carrier  of  fluid  from  the  frontal 
region  of  the  ethmoidal  infundibulum  (Figs.  127  and  197). 

The  ethmoidal  bulla  (bulla  ethmoidale)  is  a  bleb-like  protuberance  of 
bone,  extremely  variable  in  size  and  shape,  projecting  from  the  medial 
surface  of  the  lateral  mass  of  the  ethmoid  under  cover  of  the  middle  nasal 
concha  (Fig.  157).  It  is  excavated  by  a  variable  number  of  ethmoidal 
cells  to  which  it  owes  its  prominence.  The  bulla  is  bounded  caudally 
and  dorsally  by  the  semilunar  hiatus  and  the  ethmoidal  infundibulum  and 
cephalically  is  limited  by  the  suprabullar  furrow  into  which  open  most  of 
the  cells  that  honeycomb  its  mass.  Occasionally  grooving  the  medial 
surface  of  the  bulla  is  a  persistent  fetal  bullar  furrow,  which  at  times 
contains  the  ostium  of  an  ethmoidal  cell  (bullar  cell).  Rarely  in  the  adult 
a  faint  infrabullar  furrow  (a  fetal  condition)  partially  separates  the  eth- 
moidal bulla  from  an  infundibular  fold  (page  31).  The  furrow  may  con- 
tain the  ostium  of  a  small  ethmoidal  cell.  The  usual  condition,  however, 
is  a  fusion  of  the  superior  and  inferior  fetal  bullar  folds  in  the  formation 
of  the  adult  ethmoidal  bulla  and  for  the  infundibular  fold  to  lose  its  iden- 
tity by  obliteration  of  the  infrabullar  furrow  (see  embryology,  page  30). 

As  stated  elsewhere,  the  ethmoidal  bulla  varies  considerably  in  size, 
at  times  feebly  developed,  again  assuming  relatively  large  proportions  (Fig. 
124).  The  size  of  the  bulla  greatly  influences  the  width  of  the  semilunar 
hiatus.  The  bulla  when  large  may  come  into  actual  contact  with  the 
free  margin  of  the  uncinate  process.  Indeed,  it  may  impinge  upon  the 
confines  of  the  uncinate  process  and  crowd  it  away  (Fig.  161).  When 


LATERAL  WALL  OF  NASAL  FOSSA 


95 


the  bulla  is  feebly  developed  the  semilunar  hiatus  is  of  considerable  width 
and  the  drainage  of  the  ethmoidal  infundibulum  enhanced  thereby  (Fig 


The  suprabullar  furrow  or  recess  is  a  variable,  secondary  channel 
grooving  the  lateral  wall  of  the  middle  nasal  meatus  superior  to  the  eth- 
moidal bulla,  e.g.,  between  the  latter  and  the  attached  border  of  the  middle 
nasal  concha.  Notwithstanding  that  it  varies  in  its  form,  all  specimens 
give  some  evidence  of  it.  It  may  course  ventrally  and  cephalically  almost 
to  the  cribriform  plate  of  the  ethmoid.  In  the  majority  of  cases  it  is 
limited,  however,  ventrally  by  fusion  between  the  ethmoidal  bulla  and 
the  attached  border  of  the  middle  concha.  Similar  fusion  may  limit  it 
dorsally.  Not  infrequently  multiple  points  of  fusion  break  the  suprabullar 
recess  into  several  compartments,  each  receiving  the  ostium  of  an  eth- 
moidal cell  located  in  the  bulla  or  elsewhere  (Figs.  40  and  197).  Again, 
the  whole  recess  may  deepen  and  sink  into  the  body  of  the  ethmoidal 
bulla,  thus  forming  a  large  single  bullar  cell,  which  causes  the  ethmoidal 
bulla  to  be  large  and  to  encroach  upon  neighboring  structures.  Ethmoidal 
cells  constantly  develop  from  the  suprabullar  recess  and  in  the  adult 
such  cells  are,  of  course,  in  communication  with  it.  Rarely  the  frontal 
sinus  seems  to  have  its  genesis  from  this  recess. 

The  frontal  recess  (ascending  ramus  of  the  middle  nasal  meatus)  is  a 
direct  extension  developmentally  of  the  middle  meatus  proper  and  is 
intimately  related  to  the  genetic  and  adult  anatomy  of  the  frontal 
sinus  and  certain  of  the  anterior  ethmoidal  cells.  Its  detailed  adult 
anatomy  is  discussed  under  the  nasof  rental  connections  (page  160)  and 
the  ethmoidal  cells  (page  205). 

The  superior  nasal  concha  (concha  nasalis  superior)  is  a  short  thin 
lamina  of  bone  which  projects  from  the  lateral  ethmoid  mass  and  over- 
hangs the  superior  nasal  meatus  and  the  structures  contained  therein. 
However,  it  is  much  less  operculating  in  character  than  the  middle  nasal 
concha  (Figs.  129  and  146).  The  superior  concha  of  the  adult  is  usually 
represented  by  a  horizontal  or  descending  ramus  only.  Occasionally, 
however,  a  vertical  or  ascending  ramus  is  differentiated  as  well.  The 
osseous  lamella  is  covered  by  a  thin  mucous  membrane  directly  continued 
from  the  general  nasal  lining.  The  mucosa  is  thinner  and  much  less 
erectile  in  character  than  that  of  the  middle  and  inferior  conchae.  In  the 
series  of  264  lateral  nasal  walls  examined,  the  superior  nasal  concha  was 
absent  twice. 

The  superior  nasal  meatus  (meatus  nasi  medius)  is  a  channel-like 
depression  on  the  medial  surface  of  the  lateral  ethmoidal  mass  immedi- 


96  THE  DEFINITIVE  NOSE 

ately  caudal  to  the  attached  border  of  the  superior  nasal  concha  and  is 
often  referred  to  as  the  ethmoidal  fissure  (Figs.  146  and  195).  It  is,  as  a 
rule,  not  angulated  into  ascending  and  descending  limbs  as  is  the  middle 
meatus,  but  forms  a  fairly  straight  channel  directed  caudalward  and  dor- 
salward.  Moreover,  it  is  approximately  half  the  length  of  the  middle 
meatus  and  overhung  to  a  less  degree.  Occasionally  the  superior  meatus 
has  a  prominent  ascending  limb  grooving  the  lateral  ethmoidal  mass 
almost  to  the  cribriform  plate  (Fig.  29).  Not  infrequently  an  accessory 
concha  molds  the  lateral  wall  of  the  superior  nasal  meatus  and  divides 
the  latter  into  superior  and  inferior  recesses.  The  inferior  recess  is  usually 
the  better  developed  and  often  "erodes"  into  the  superior  surface  of  the 
attached  border  of  the  concha  media  in  the  formation  of  a  sinus-like 
depression  which  lends  prominence  to  the  crista  suprema  of  the  middle 
concha.  A  thin  mucous  membrane  lines  the  superior  meatus  and  extends 
into  the  posterior  ethmoidal  cells  which  communicate  with  the  ventral 
extremity  of  the  superior  meatus  and  with  its  superior  and  inferior 
recesses. 

The  first  supreme  nasal  concha  (concha  nasalis  suprema  I)  persists 
in  the  adult  in  approximately  60  per  cent,  of  individuals.  It  is  a  very 
short,  thin  lamina  projecting  from  the  dorsolateral  portion  of  the  lateral 
ethmoidal  mass,  slightly  overhanging  the  corresponding  nasal  meatus. 
A  very  thin  mucosa  covers  it. 

The  first  supreme  nasal  meatus  (meatus  nasi  supremus  I)  is  a  shallow, 
short  furrow  located  on  the  dorsolateral  aspect  of  the  medial  surface  of 
the  lateral  ethmoidal  mass  immediately  caudal  to  its  corresponding 
concha.  As  the  latter,  the  meatus  is  present  in  about  60  per  cent,  of 
individuals,  and  in  approximately  75  per  cent,  of  them  a  posterior  eth- 
moidal cell  communicates  with  it,  indicating  a  genesis  of  an  ethmoidal 
cell  from  it  in  the  fetus  (see  page  23).  A  thin  mucous  membrane  lines 
the  meatus  and  the  related  ethmoidal  cell  (Figs.  26  and  127). 

The  sphenoethmoidal  recess  (recessus  sphenoethmoidalis)  is  a  re- 
stricted portion  of  the  nasal  fossa  located  cephalic  and  dorsal  to  the  high- 
est or  most  cephalic  ethmoidal  concha  that  may  be  present  in  the  particular 
case  (in  approximately  40  per  cent,  of  cases  the  concha  superior  is  the 
caudal  boundary  and  in  60  per  cent.,  the  concha  suprema  I).  The  recess 
is  bounded  above  (cephalically)  by  the  cribriform  plate  of  the  ethmoid 
bone  and  dorsally  by  the  ventral  surface  of  the  body  of  the  sphenoid 
bone.  The  recess  is  lined  by  a  very  thin  mucous  membrane  and  contains 
the  ostium  of  communication  of  the  sphenoidal  sinus  (ostium  sphenoidale) 
on  its  dorsal  wall.  The  sphenoethmoidal  recess  must  not  be  confused 


LATERAL  WALL  OF  NASAL  FOSSA  97 

with  the  superior  and  the  supreme  nasal  meatuses.  Nasal  meatuses  are 
always  located  caudal  (inferior)  to  the  corresponding  nasal  conchae. 

The  second  and  third  supreme  nasal  conchae  (conchae  nasales  supre- 
mae  II  et  III)  and  the  related  meatuses  (meatus  nasi  supremus  II  et  III) 
are  rarely  present  in  the  adult  human  body.  Notwithstanding  that  these 
structures  are  at  times  well  differentiated  in  the  fetus  (especially  the 
concha  suprema  II)  they  usually  undergo  regression  in  late  fetal  and  early 
infantile  life  and  are  seldom  seen  after  the  second  year  (Figs.  26  and  28). 
In  the  series  of  264  adult  lateral  nasal  walls  but  four  specimens  were  found 
with  four  ethmoidal  conchae,  e.g.,  the  conchae  nasales  media,  superior, 
suprema  I,  et  suprema  II.  In  no  instance  was  a  persistent  concha  su- 
prema III  observed. 

The  agger  nasi  (nasoturbinal)  is  a  low  ridge-like  elevation  in  the 
macerated  skull  on  the  medial  surface  of  the  frontal  process  of  the  maxilla, 
coursing  caudal-  and  ventralward  from  the  ventral  extremity  of  the 
middle  nasal  concha  immediately  ventrocephalic  to  the  nasal  atrium  and 
extending  more  or  less  parallel  to  the  bridge  of  the  nose.  In  most  mammals 
the  nasoturbinal  is  well  developed,  while  in  man  it  is  extremely  rudiment- 
ary, reaching  its  maximum  development,  as  a  rule,  in  the  late  fetus  and  the 
infant.  In  the  recent  state  the  nasal  mucous  membrane  gives  the  agger 
nasi  additional  prominence.  Not  infrequently  ethmoidal  cells  grow  out 
from  the  ethmoidal  infundibulum  and  from  the  frontal  recess  into  the  agger 
nasi,  forming  the  so-called  agger  cells  (Figs.  153  and  197). 

The  nasal  atrium  (atrium  nasi,  atrium  meatus  medii)  is  a  triangular 
expansion  of  the  nasal  fossa  beyond  the  nasal  vestibule.  The  expansion  is 
primarily  due  to  a  variable  saucer-like  depression  or  lateral  arching  in  the 
lateral  nasal  wall  in  advance  of  the  entrance  to  the  middle  nasal  meatus. 
Coursing  obliquely  caudalward  and  ventralward  the  agger  nasi  delimits 
the  nasal  atrium  from  the  deep  surface  of  the  dorsum  of  the  nose.  In  a 
sense  the  atrium  is  the  related  meatus  of  the  agger  nasi  (nasoturbinal) 
and  is  much  more  prominent  in  those  forms  with  a  well-developed  naso- 
turbinal. In  man  it  frequently  encroaches  upon  the  lumen  of  the  maxil- 
lary sinus  by  causing  the  nasal  or  medial  wall  of  the  sinus  to  be  convex 
(Fig.  146). 

The  olfactory  sulcus  (sulcus  olfactorius,  carina  nasi)  is  a  channel- 
like  space  lying  ventral  to  the  agger  nasi  and  limited  by  the  rounded  or 
arched  confluence  of  the  medial  and  lateral  nasal  walls.  It  extends  from  the 
vestibulum  nasi  along  the  ental  surface  of  the  dorsum  of  the  nose  to  the 
pars  olfactoria  of  the  nasal  fossa.  At  the  roof  of  the  nose  it  becomes 
confluent  with  the  space  immediately  caudal  to  the  cribriform  plate  which 


98  THE   DEFINITIVE   NOSE 

in  turn  becomes  the  recessus  sphenoethmoidalis  farther  dorsally.  The 
latter  contains  the  ostium  sphenoidale  on  its  dorsal  wall.  It  is  obvious, 
therefore,  that  by  following  the  several  segments  of  this  continuous  chan- 
nel along  the  dorsum  and  roof  of  the  nose  the  ostium  of  the  sphenoidal 
sinus  may  be  located.  Moreover,  it  is  believed  that  odoriferous  gaseous 
substances  readily  reach  the  olfactory  mucosa  through  the  olfactory  sulcus 
(Fig.  146). 


1II-THE  MAXILLARY  SINUS 


CHAPTER  III 

THE  MAXILLARY  SINUS 

THE  FETAL  STAGE 

The  maxillary  sinus  (sinus  maxillaris,  antrum  of  Highmore),  primi- 
tively a  pouching  or  evagination  of  the  mucous  membrane  of  the  floor  or 
lateral  wall  of  the  ethmoidal  infundibulum  (infundibulum  ethmoidale), 
is  evident  about  the  seventieth  day  of  fetal  life.  It  is  difficult  of  appre- 
ciation in  its  initial  state  from  an  examination  of  serial  sections  only,  but  is 
well  demonstrated  by  reconstructing  at  a  considerable  magnification  the 
ethmoidal  infundibulum.  The  rudiment  or  anlage  of  the  sinus  is  usually 
represented  by  a  single  pouch;  however,  two  pouches  growing  side  by  side 
from  the  ethmoidal  infundibulum  have  been  observed  by  the  writer.  Again, 
the  pouch  may  be  relatively  large  at  the  outset,  making  it  difficult  to  deter- 
mine where  the  ethmoidal  infundibulum  ends  and  where  the  initial  rudi- 
ment or  maxillary  sinus  begins.  In  such  cases  the  ethmoidal  infundibulum 
is  in  a  sense  a  part  of  the  maxillary  sinus.  One  should,  however,  consider 
the  maxillary  sinus  as  developing  from  the  pre-existing  furrow  (infundi- 
bulum ethmoidale)  and  not  consider  the  latter  a  part  of  the  sinus.  How- 
ever, as  stated  before,  it  is  difficult  at  times  to  draw  this  distinction,  es- 
pecially so  when  the  primitive  maxillary  sinus  is  extensive  and  occupies 
the  greater  portion  of  the  infundibulum  ethmoidale  in  its  early  pouching 
(Figs.  76-77). 

The  duplication  and  extensive  pouching  of  the  primitive  maxillary 
sinus,  occasionally  encountered,  is  in  accord  with  adult  conditions.  The 
adult  ostium  maxillare  varies  from  a  small  round  or  oval  aperture  to  a  long 
slit-like  cleft,  and  is  either  single  or  duplicate.  The  initial  doubling  of 
the  maxillary  sinus  doubtless  explains  some  of  the  duplications  of  the 
adult  ostium  maxillare.  It  is  not  unreasonable  to  believe  that  in  some 
instances  fusion  of  the  double  maxillary  pouch  takes  place  distally, 
leaving  the  points  of  initial  outgrowth  as  the  duplicate  ostium.  Further- 
more, the  doubling  of  the  primitive  maxillary-sinus  pouch  may  explain 
some  of  the  rare  double  adult  maxillary  sinuses,  each  with  an  independent 
ostium  in  communication  with  the  ethmoidal  infundibulum,  i.e.,  each 
evaginating  sac  developing  independent  of  its  mate. 


102  THE  MAXILLARY  SINUS 

Instances  in  which  one  of  two  unilateral  maxillary  sinuses  communi- 
cated with  the  superior  nasal  meatus  have  been  recorded  by  Zuckerkandl 
and  others.  The  writer  recently  made  a  number  of  similar  observations 
(Figs.  73  and  101).  There  is  no  doubt  whatever  that  the  additional 
maxillary  sinus  in  these  cases  is  truly  an  ethmoid  cell  which  developed 
beyond  the  confines  of  the  ethmoid  field  into  the  maxilla.  Genetically, 
such  a  sinus  is  ethmoid;  topographically,  maxillary.  Indeed,  the  maxilla 


FIG.  76.  FIG.   77. 

FIGS.  76  and  77. — Drawings  of  reconstructions  of  portions  of  the  right  nasal  fossa  including  the 
meatus  nasi,  infundibulum  ethmoidale,  hiatus  semilunaris  and  sinus  maxillaris.  The  figure  to 
the  reader's  left  is  from  a  human  embryo  aged  105  days  and  that  to  the  right  from  a  human  embryo 
aged  1 20  days.  It  must  be  understood  that  both  models  represent  cavity  and  are,  therefore,  negatives. 
Particularly  note  the  maxillary  sinus  at  these  ages,  and  the  unlike  size  and  shape  of  the  ostium  maxil- 
lare  in  the  two  specimens.  X  12. 

Mns  =  meatus  nasi  superior;  Hs  =  hiatus  semilunaris;  Mnm  =  meatus  nasi  medius;  le  =  in- 
fundibulum ethmoidale;  Om  =  ostium  maxillare;  Sm  =  sinus  maxillaris;  Mni  =  meatus  nasi  in- 
ferior. 

regularly  aids  in  completing  the  osseous  boundaries  of  certain  ethmoid 
cells.  Briihl's  case  in  which  an  additional  maxillary  sinus,  that  is,  a 
sinus  present  in  duplicate,  communicated  with  the  inferior  nasal  meatus 
is  difficult  of  genetic  interpretation,  since  ordinarily  no  paranasal  sinus 


FETAL  STAGE 


103 


communicates  with  this  meatus  and  none  develops  from  it.  In  all  prob- 
ability the  ostium  of  communication  in  Briihl's  case  was  secondary  and 
doubtless  formed  in  a  manner  similar  to  the  very  common  ostium  maxillare 
accessorium  found  in  the  middle  nasal  meatus  in  connection  with  the  usual 
single  maxillary  sinus  (Fig.  108). 

The  frequent  great  dimensions  of  the  adult  ostium  maxillare  may  be 
due  to  a  merging  of  two  or  more  primitive  maxillary  pouches,  or  the  primi- 
tive pouching  may  have  been  single,  but  very  extensve,  occupying  a  goodly 
portion  of  the  floor  of  the  ethmoidal  infundibulum. 


FIG.  79. 


FIG.  81. 

FIGS.  78-81. — The  lining  mucous  membranes  of  maxillary  sinuses  removed  from  formalized 
cadavers.  The  illustrations  represent  the  exact  shapes  of  the  maxillary  sinus  as  found  in  these  bodies. 
X  4-  (After  J.  P.  S.) 

Fig.  78,  from  a  fetus  aged  4  months;  Fig.  79,  from  a  fetus  at  term;  Fig.  80,  from  a  child  aged  18 
to  20  months;  Fig.  81,  from  a  child  aged  20  to  23  months. 

The  early  maxillary  sinus  is  for  a  time  a  slit-like  cavity  in  the  mem- 
branous lateral  wall  of  the  nose.  It  extends  inferiorly  into  the  recess 
formed  by  the  union  of  the  lateral  cartilaginous  plate  with  that  of  the 
inferior  nasal  concha.  By  resorption  of  the  cartilaginous  nasal  capsule 
intervening  between  the  maxilla  and  the  developing  maxillary-sinus  sac 
the  latter  ultimately  comes  into  actual  and  direct  relationship  with  the 
maxilla.  By  the  simultaneous  processes  of  resorption  of  surrounding 
bone  and  the  growth  of  the  maxillary  pouch,  the  primitive  cavity  gains 
more  and  more  capacity  and  sinks  into  the  body  of  the  maxilla.  It  has 


104 


THE  MAXILLARY  SINUS 


its  greatest  measure  in  the  ventrodorsal  direction,  while  mediolaterally 
the  cavity  occupies  comparatively  little  space.  In  embryos  aged  from 
100  to  105  days  the  ventrodorsal  measurement  is  about  2  mm.  In  a  120- 
day  embryo  the  distance  is  about  2.5  mm.  In  a  loo-day  embryo  the  most 
ventral  spur  of  the  sinus  is  about  6.5  mm.,  and  the  most  dorsal  spur  8.5 
mm.  from  the  tip  of  the  nose  (Figs.  78,  79,  80  and  81). 

It  will  be  remembered  in  the  embryo  the  processus  alveolaris  of  the 
maxilla  is  in  proximity  to  the  orbit,  and  when  one  recalls  the  fact  that  the 
unerupted  teeth  are  contained  in  this  situation,  it  at  once  becomes  evident 
that  the  maxillary  sinus  must  be  correspondingly  small  at  this  time. 
Because  of  these  facts  the  sinus  of  a  7-month  fetus  measures  only  5  mm. 
in  the.  ventrodorsal  plane  and  in  a  fetus  at  term  approximately  7  mm. 
During  the  latter  months  of  intrauterine  life  the  sinus  gains  in  the  medio- 
lateral  plane  and  at  term  measures  from  3  to  4  mm.  The  extension  of  the 
maxillary  sinus  into  the  body  of  the  maxilla  takes  place  para  passu  with 
the  growth  of  the  face  (Fig.  84). 

The  appended  table,  A,  gives  the  approximate  size  of  the  maxillary 
sinus  at  various  stages  of  fetal  life : 


TABLE  A 


A                                                             Ventrodorsal 
(length) 

Mediolateral 
(width) 

Cephalocaudal 
(height)       . 

ioo  days  2.0  mm. 
120  days  2.5  mm. 
210  days  5.0  mm. 
Term   fetus  7.0  to  8.0  mm. 

Potential 
Potential 
2.0  mm. 
3.0  to  4.0  mm. 

0.5  mm. 
0.8  mm. 
4.0  mm. 
4.0  to  6.0  mm. 

THE  CHILDHOOD  STAGE1 

The  size  and  shape  of  the  maxillary  sinus  at  birth  varies  considerably 
as  is  evidenced  by  a  study  of  a  large  number  of  still-born  babies;  indeed, 
the  variation  continues  into  adult  life.  However,  one  must  not  be  misled 
by  an  apparent  variance  in  size,  due  to  sectioning  the  sinus  in  unlike 
planes — horizontal,  coronal  and  sagittal.  Writers  often  give  measure- 
ments without  stating  the  plane  and  this  obviously  leads  to  error  and  an 
apparent  rather  than  a  real  discrepancy  in  results. 

The  ventrodorsal  (length)  measurement  is  always  the  greatest  and 
up  to  the  end  of  the  third  year  the  cephalocaudal  (height)  measurement 
of  the  sinus  is  intermediate  between  the  ventrodorsal  and  mediolateral 

1  The  term  "childhood"  is  sometimes  restricted  to  the  time  between  infancy  and  youth;  however, 
here  the  term  is  meant  to  apply  to  the  period  from  birth  to  puberty. 


CHILDHOOD  STAGE 


105 


(width).  However,  during  the  sixth  year  the  mediolateral  measurement 
gains,  but  seldom  exceeds  the  cephalocaudal  measurement.  The  cavity 
is  never  spherical  as  is  often  stated.  For  some  time  the  maxillary  sinus 


FIG.   82. — Photograph    of    a    semi-frontal    section    of    a    child's  face  aged  from  16  to   18  months. 

Particularly  note  the  infraorbital  canal  and  nerve  and  the  maxillary  sinus.       X  0.8 

Ninforb  =  Nervus  infraorbitalis;  Smax  =  Sinus  maxillaris. 

is  not  sufficiently  developed  in  width  to  reach  beneath  the  orbit.  By 
the  end  of  the  first  year  it  has  grown  sufficiently  in  this  plane  to  extend 
beneath  the  orbit,  but  not  beyond  the  position  of  the  infraorbital  canal. 


ffeatus 


v*v 


FIG.   83. — A  frontal  section  through  the  nasal  fossae  and  the  paranasal  sinuses  at  the  level  of  the 
ostium  of  the  maxillary  sinus  in  a  child  aged  approximately  seven  years.       X  i. 

and  at  the  twentieth  month  it  has  elongated  in  the  ventrodorsal  plane 
to  20  mm.,  and  has,  as  a  rule,  extended  above  the  rudimentary  first  per- 
manent molar  tooth.  During  the  third  and  fourth  years  the  maxillary 


io6  THE  MAXILLARY  SINUS 

sinus  makes  a  conspicuous  growth  in  the  mediolateral  plane  (width). 
By  the  seventh  year  the  sinus  measures  on  the  average  27  mm.  in  the 
ventrodorsal  plane,  17  mm.  in  the  superoinferior  plane,  and  18  mm.  in  the 
mediolateral  plane  (Fig.  83). 

It  is  generally  stated  that  the  deciduous  teeth  hold  the  maxillary 
sinus  in  check,  and  that  the  cavity  rapidly  assumes  larger  dimensions  as 


FIG.   84. — Skulls  indicating  the  increase  of  distance  between  the  infraorbital  foramen  and  the  mid- 
point of  the  upper  jaw  from  birth  to  adult  age. 

the  first  dentition  progresses.  The  author  finds,  however,  that  the  growth 
of  the  sinus  is  rather  uniform  and  that  the  first  dentition  has  little  to  do 
with  any  rapid  increase  in  the  size  of  the  cavity.  The  age  of  the  child, 
dentition,  and  the  size  of  the  maxillary  sinus  progress  para  passu.  It  is, 
however,  obvious  that  until  the  teeth  erupt  and  the  alveolar  process 
develops  there  can  be  little  room  for  the  maxillary  sinus  (Fig.  84). 


CHILDHOOD  STAGE 


107 


It  is  well  to  remember  that  in  the  infant  the  inferior  nasal  meatus 
does  not  come  into  the  same  intimate  relationship  with  the  maxillary 
sinus  as  in  the  periods  following  the  eighth  to  the  twelfth  years.  The 
relations  with  the  middle  nasal  meatus  are  much  more  intimate  and  should 
be  borne  in  mind  when  the  maxillary  sinus  is  to  be  explored  endonasally 
in  the  young  child.  Moreover,  the  inferior  nasal  meatus  is  exceedingly 
narrow  at  this  time  due  to  the  relatively  large  inferior  nasal  concha  and 
the  heavy  mucosa  (see  page  20).  Seemingly,  the  middle  nasal  meatus 
and  the  general  nasal  cavity  alone  serve  as  respiratory  passages  at  this 
time.  By  the  eleventh  or  twelfth  year  the  inferior  meatus  is  enlarged 
and  the  maxillary  sinus  has  grown  sufficiently  toward  the  alveolar  process 
to  be  accessible  for  puncture  in  the  usual  adult  site,  e.g.,  in  the  inferior 
nasal  meatus.  However,  the  writer  has  observed  maxillary  sinuses 
in  intimate  relationship  with  the  inferior  nasal  meatus  at  term  (Fig. 
156). 

The  operator  needs  to  be  cautious  in  endonasal  procedures  on  the 
maxillary  sinus  of  the  infant  from  the  inferior  meatus.  The  instrument 
is  readily  pushed  through  the  soft  structures  of  the  cheek  and  the  sinus 
cavity  missed  entirely,  or  both  the  medial  and  lateral  walls  may  be  pene- 
trated. Again,  it  would  seem  wise  to  use  the  middle  nasal  meatus  until 
after  the  eruption  of  most  of  the  permanent  teeth.  The  operator  must 
always  remember  that  the  rudiments  of  both  the  deciduous  and  permanent 
teeth  are  present  in  the  maxilla  at  the  time  of  birth,  there  undergoing 
further  development  up  to  the  time  of  dentition.  Injury  to  a  "tooth 
germ"  would  lead  either  to  death  of  the  part  or  to  the  eruption  of  a  de-'' 
formed  tooth  ultimately.  Surgically,  in  both  the  endonasal  and  the 
canine  fossa  approaches  of  the  maxillary  sinus  in  the  young  child,  the 
narrow  mediolateral  (transverse)  diameter  of  the  maxillary  sinus  must 
not  be  forgotten. 

The  appended  table,  B,1  gives  the  size  of  the  maxillary  sinus  in  a 
series  of  specimens  from  birth  to  1 5  years  of  age.  Owing  to  the  scarcity 
of  material  at  the  childhood  period  some  observations  are  limited  to  few 
specimens.  After  the  fifteenth  year  the  sinus  in  a  sense  passes  into 
the  adult  stage.  It  will  be  noted  that  after  this  period  the  sinus  enlarges 
principally  in  its  vertical  diameter  (superoinferior)  and  in  its  diagonals. 
The  ventrodorsal  and  mediolateral  measurements  are  nearly  the  adult 
average : 

1  See  also  Warren  B.  Davis,  Nasal  Accessory  Sinuses,  Philadelphia,  1914,  for  valuable  and  in- 
structive tables  of  measurements  of  the  paranasal  sinuses  of  the  childhood  period. 


io8 


THE  MAXILLARY  SINUS 
TABLE  B 


Age 

Ventrodorsal               Cephalocaudal 
(length)                         (height) 

Mediolateral 
(width) 

Newborn  

1 
7.0  to    8.0  mm.      4.0  to    6.0  mm. 

3.0  to    4.0  mm. 

6  months  

10.0  to  10.5  mm.      4.0  to    5.0  mm. 

4.0  to    4.5  mm. 

9  months  

n.o  to  14.0  mm.      5.0  to    5.0  mm. 

5.0  to    5.5  mm. 

i  year  

14.0  to  16.0  mm.      6.0  to    6.5  mm. 

5.0  to    6.0  mm. 

1.5  years  

20.0  to  20.5  mm.      8.0  to    9.0  mm. 

6.0  to    6.5  mm. 

2  years  

21.0  to  22.0  mm.     10.0  to  n.o  mm. 

8.0  to    9.0  mm. 

3  years  

22.0  to  23.0  mm.     ii.  o  to  12.0  mm. 

9.0  to  10.0  mm. 

6  years  

27.0  to  28.0  mm.     16.0  to  17.0  mm. 

16.0  to  17.0  mm. 

8  years  

28.0  to  29.0  mm.     17.0  to  17.5  mm. 

1  7.0  to  18.0  mm. 

10  years  

30.0  to  31.0  mm.     17.5  to  18.0  mm. 

19.0  to  20.0  mm. 

1  2  years  

31.0  to  32.0  mm.     18.0  to  20.0  mm. 

19.0  to  20.0  mm. 

15  years  

31.0  to  32.0  mm.     18.0  to  20.0  mm. 

19.0  to  20.0  mm. 

It  is  of  interest  here  to  note  adult  average  measurements  of  the  maxil- 
lary sinus  for  comparison:  ventrodorsal  34  mm.,  superoinferior  33  mm., 
and  mediolateral  23  mm. 

The  skiagram  is  of  great  value  in  early  childhood  in  following  the 
growth  of  the  maxillary  sinus  and,  since  considerable  variation  in  the  man- 
ner of  pneumatization  of  the  body  of  the  maxilla  is  met  with,  skiagraphy 
is  almost  indispensable  when  operative  procedures  become  necessary. 

Even  though  the  maxillary  sinus  is  a  cavity  of  considerable  size  in  the 
newborn,  often  measuring  8  by  4  by  6  mm.,  it  is  not  always  demon- 
strable in  skiagrams.  This  is  probably  due  to  the  slit-like  shape  of  the 
sinus  and  the  fact  that  it  hugs  the  lateral  wall  of  the  nasal  fossa  closely. 
Even  at  this  early  time  the  sinus  is  of  considerable  clinical  importance. 
At  the  end  of  the  first  year  the  maxillary  sinus  is  still  medial  to  the  infra- 
orbital  foramen.  The  skiagram  usually  delineates  it  well,  since  the  can- 
cellous  maxilla  readily  allows  the  rays  to  pass.  Later,  say  at  the  end  of  the 
second  year,  the  maxillary  sinus  has  pneumatized  up  to  the  infaorbital 
foramen  and  is  more  or  less  triangular  in  shape  and  is  somewhat  obscured 
in  skiagrams  by  shadows  of  the  petrous  portion  of  the  temporal  bone  and 
the  unerupted  permanent  teeth  (Fig.  92).  However,  it  is  clearly  indi- 
cated along  the  infraorbital  margin.  At  5  years  of  age  the  maxillary 
sinus  has  extended  considerably  beyond  the  infraorbital  canal.  At  9 
years  it  has  pneumatized  the  zygomatic  process  of  the  maxilla  in  the  forma- 
tion of  the  recessus  zygomaticus.  The  extension  into  the  zygomatic 
process  is  as  a  rule  not  visible  on  X-ray  plates. 

Clinically,  it  is  very  important  to  know  the  degree  of  development  in 
a  particular  case  of  the  recessus  alveolaris  when  the  maxillary  sinus  is 
operated  upon  by  way  of  the  nasal  fossa.  While  the  age  of  the  child  is  a 


ADULT  STAGE  ICQ 

valuable  guide  (see  table  B,  page  108),  the  skiagram  after  all  must  give 
the  surgeon  the  definite  and  precise  information  concerning  the  pneumati- 
zation  of  the  alveolar  process  in  the  case  before  him.  In  the  interpretation 
of  skiagrams  one  must  recall  that  in  ventrodorsal  pictures  of  the  maxillary 
sinus  the  second  and  third  (sometimes  the  first  also)  molar  teeth  throw  a 
heavy  shadow  upon  the  floor  of  the  sinus,  which  is  confusing.  Haike  has 
shown  that  the  recessus  alveolaris,  e.g.,  the  degree  of  pneumatization  of 
the  alveolar  process,  is  best  demonstrated  in  the  child  by  taking  a  profile 
view  of  the  face.  The  profile  skiagrams  show  this  recess  in  children  as 
early  as  the  sixth  and  seventh  year,  especially  so  at  the  ventral  part  of  the 
floor  of  the  maxillary  sinus.  It  is  well  to  remember,  however,  that  the 
alveolar  process  of  the  maxilla  is  not  fully  pneumatized  by  the  alveolar 
recess  of  the  maxillary  sinus  until  the  time  when  the  permanent  teeth  have 
erupted. 

THE  ADULT  STAGE 

General  Considerations. — The  adult  maxillary  sinus  was  known  to 
Galenus  (130-201),  but  Dr.  Nathaniel  Highmore  was  the  first  to  give  any 
detailed  description  of  it.  In  his  work  (1651),  "  Corporis  Humani  Dis- 
quisitio  Anatomica"  he  describes  the  cavity  in  the  maxilla,  to  which  his 
attention  was  drawn  by  a  lady  patient,  in  whom  an  abscess  of  this  cavity, 
since  frequently  referred  to  as  the  antrum  of  Highmore,  was  drained  by 
the  extraction  of  the  left  canine  tooth.  The  sinus  described  by  Highmore 
must  have  been  exceptionally  large  since  the  canine  tooth  does  not  as  a 
rule  come  into  relationship  with  the  sinus.  Some  writers  even  today  refer 
to  the  canine  tooth  as  the  proper  drainage  site  in  sinus  treatment  when 
the  endonasal  approach  is  not  utilized.  The  belief  that  the  canine  tooth 
socket  commonly  bears  an  intimate  relationship  to  the  floor  of  the  maxil- 
lary sinus  is  archaic  and  must  be  abandoned. 

The  adult  maxillary  sinus,  located  in  the  body  of  the  maxilla,  is  the 
largest  of  the  paranasal  sinuses,  save  in  exceptional  cases  when 'it  is  com- 
paratively small  and  exceeded  in  size  by  the  frontal  and  sphenoidal  sinuses. 
It  lies  lateral  to  the  cavum  nasi  and  resembles  in  shape  a  three-sided 
pyramid.  It  follows  in  the  main  the  shape  of  the  body  of  the  maxilla; 
and  may  be  described  as  having  a  roof,  a  floor,  and  three  walls.  The 
walls  of  the  sinus  vary  in  thickness,  usually  from  5  to  8  mm.,  but  may  be 
reduced  to  a  papery  delicacy.  The  writer  has,  indeed,  observed  dehis- 
cences  in  the  facial  or  ventral  osseous  wall  of  the  sinus.  The  median  wall 
or  base  is  directed  toward  the  cavum  nasi  and  the  apex  extends  into  the 
median  root  of  the  processus  zygomaticus  of  the  maxilla,  or  beyond  it  into 
the  maxillary  border  of  the  zygomatic  bone. 


no  THE  MAXILLARY  SIN'US 

The  ventral  wall  of  the  cavity  corresponds  to  the  anterior  or  facial 
surface  of  the  maxilla,  looking  ventrolaterally.  Part  of  this  wall  is  at 
times  greatly  approximated  to  the  dorsal  wall  and  base  of  the  sinus  due  to 
a  very  prominent  canine  fossa  (fossa  canina).  Occasionally  the  whole 
ventral  wall  bulges  markedly  into  the  cavity  of  the  maxillary  sinus. 


Sinus  fronJMlis  dexter 


Sinus  froti£a2is  sinister 


Jfecessus  cdvcolaris  sinus  max. 


FIG.  85.  —  Photograph  of  a  skull  with  the  frontal  and  maxillary  sinuses  exposed  for  study.  Par- 
ticularly note  the  asymmetry  of  the  frontal  sinuses  and  the  bulla-like  appearance  of  the  left  frontal 
sinus  (see  text,  page  152).  Note  also  the  extreme  development  of  the  palatine  recess  of  the  maxillary 
sinus.  On  both  sides  the  maxillary  sinus  extends  markedly  into  the  palatine  process  of  the  maxilla, 
thereby  gaining  a  conspicuous  relationship  to  the  floor  of  the  nasal  fossa. 

The  dorsal  wall  of  the  sinus  corresponds  to  the  infratemporal  surface 
of  the  maxilla.  It  is  a  thin  plate  of  bone,  also  forming  the  ventral  bound- 
ary of  the  infratemporal  and  pterygopalatine  fossae.  The  dorsal  is  usually 


ADULT  STAGE  in 

the  thickest  of  the  sinus  walls.  It  is,  however,  occasionally  extremely 
thin  (the  processus  alveolaris  being  recognized  as  the  floor  of  the  cavity 
and  not  as  a  wall). 

The  median  wall  or  base  is  directed  toward  the  cavum  nasi.  It 
normally  presents  a  very  irregular  orifice  (hiatus  maxillaris)  in  the  dis- 
articulated bone.  In  the  articulated  skull  the  hiatus  is  partly  filled  in  by 
the  pars  perpendicularis  of  the  palate  bone,  the  processus  uncinatus  of  the 
ethmoid  bone,  the  processus  maxillaris  of  the  inferior  nasal  concha  and  a 
portion  of  the  lacrimal  bone.  In  the  recent  and  living  state  the  nasal 
mucous  membrane  bridges  over  the  dehiscences  or  defects  in  the  osseous 
median  wall,  covers  the  bones  and  is  continued  into  the  maxillary  sinus 
in  the  formation  of  a  rounded  opening  (the  ostium  maxillare).  The  latter 
may  be  duplicated,  but  such  duplication  must  not  be  confused  with  the 
ostium  maxillare  accessorium,  which  is  a  direct  passageway  between 
the  sinus  and  the  nasal  fossa.  The  ostium  maxillare  (or  ostia  maxillaria) 
establishes  communication  between  the  sinus  and  the  infundibulum  eth- 
moidale.  The  medial  wall  immediately  inferior  to  the  attachment  of  the 
inferior  nasal  concha  is  thin  and  easily  punctured.  This  wall  also  forms 
the  lateral  boundary  of  the  nasal  fossa  which  often  encroaches  upon  and 
reduces  the  size  of  the  cavity  of  the  maxillary  sinus.  The  nasal  fossa  is, 
of  course,  correspondingly  increased  in  size  (Fig.  85). 

The  roof  of  the  maxillary  sinus  is  a  very  thin  plate  of  bone,  at  times 
of  a  papery  delicacy,  forming  the  floor  of  the  orbit  and  the  orbital  surface  of 
the  maxilla.  Not  infrequently  it  is  modeled  by  a  ridge  thrown  into  relief 
by  the  infraorbital  canal.  In  some  instances,  the  ridge  is  replaced  by 
a  groove  which  is  covered  over  by  the  mucous  membrane  of  the  maxillary 
sinus.  At  times  the  roof  of  the  sinus  is  partially  divided  into  two  plates, 
separated  by  ethmoidal  air  cells  (Fig.  102).  Occasionally  the  palate  bone 
aids  in  forming  the  roof  of  the  maxillary  sinus. 

The  ftoor  of  the  maxillary  sinus  is  formed  by  the  processus  alveolaris 
of  the  maxilla.  It  is  by  far  the  thickest  of  the  osseous  boundaries  of  the 
cavity — the  thickness  of  the  floor  depending  upon  the  degree  of  pneumati- 
zation  of  the  process.  In  cases  where  the  pneumatizing  process  has  been 
carried  far,  the  floor  of  the  sinus  bears  an  important  relation  to  some  of  the 
teeth  and  their  sockets.  The  floor  may  be  thrown  into  irregular  eleva- 
tions by  the  fangs  of  the  teeth,  depending  upon  the  thickness  of  the  layer 
of  spongy  bone.  The  latter  varies  in  thickness  in  different  skulls.  More- 
over, there  is  considerable  asymmetry  on  the  two  sides  of  the  same  skull. 

The  Relation  of  the  Sinus  Floor  to  the  Nasal  Floor.— The  relation  of 
the  floor  of  the  maxillary  sinus  to  the  floor  of  the  nasal  fossa  depends 


H2  THE  MAXILLARY  SINUS 

largely  upon  the  degree  of  hollowing  out  of  theprocessus  alveolaris  of  the 
maxilla.  The  degree  of  arching  of  the  hard  palate,  thereby  affecting  the 
floor  of  the  nose,  also  has  some  bearing  on  this  relation.  When  the  layer  of 
spongy  bone  is  thin,  [e.g.,  the  processus  alveolaris  markedly  pneumatized 
by  the  maxillary  sinus,  the  floor  of  the  nasal  fossa  is  caudal  to  the  floor  of 
the  sinus.  On  the  other  hand,  when  the  processus  alveolaris  is  relatively 
thick  the  floor  of  the  nasal  fossa  is  caudal  to  that  of  the  sinus.  Occasion- 
ally both  floors  are  in  the  same  plane.  When  the  ventral  (facial)  surface 
of  the  maxilla  and  the  lateral  wall  of  the  nasal  fossa  are  simultaneously 
bulging  toward  the  maxillary  sinus  and  at  the  expense  of  its  lumen,  the 
floor  of  the  nasal  fossa  is,  as  a  rule,  caudal  to  the  floor  of  the  sinus.  Not- 
withstanding these  departures,  the  majority  of  maxillary  sinuses  have  their 
floors  at  varying  distances  caudal  (below)  the  level  of  the  floor  of  the  nasal 
fossa.  In  an  examination  of  120  adult  specimens  78  were  found  in  which 
the  sinus  floor  was  the  more  dependent,  24  in  which  the  fossa  floor  was 
the  more  dependent,  and  18  in  which  the  sinus  and  fossa  floors  were  in  the 
same  plane. 

The  difference  in  levels  of  the  floors  of  the  maxillary  sinus  and  the 
nasal  fossa  varies  from  ^  to  10  mm.  C.  Reschreiter1  claims  that 
it  is  a  male  characteristic  to  find  the  sinus  floor  at  a  level  caudal  to  that  of 
the  nasal  fossa.  The  writer's  observations  do  not  confirm  this.  In  an 
examination  of  30  specimens  taken  from  female  cadavers,  20  showed  the 
sinus  floor  to  be  the  more  caudal,  6  the  nose  floor,  and  in  4  instances  the 
floors  to  be  on  the  same  level.  Moreover,  the  differences  in  level  between 
the  two  floors  varied  in  accord  with  that  given  above  for  the  male. 

Relations  of  the  Maxillary  Sinus  to  the  Teeth.— Since  the  maxillary 
sinus  varies  greatly  in  size  in  different  skulls  and  on  the  two  sides  of  the 
same  skull,  it  is  obvious  that  the  relations  of  the  teeth  to  the  sinus  cannot 
be  constant.  As  stated  before,  the  layer  of  spongy  bone  between  the 
roots  of  the  teeth  and  the  floor  of  the  maxillary  sinus  varies  in  thickness  in 
different  skulls  and  the  asymmetry  on  the  two  sides  of  the  same  skull  is  at 
times  marked.  When  the  layer  of  spongy  bone  is  relatively  thin  the 
projecting  tooth  fangs  form  elevations,  of  a  greater  or  less  degree,  on  the 
floor  of  the  sinus.  These  elevations  at  times  aid  in  recess  formation  (Figs. 
86  and  87).  Direct  communication  between  the  fangs  of  the  teeth  and 
the  mucous  membrane  of  the  sinus,  due  to  extreme  hollowing  out  of  the 
processus  alveolaris  of  the  maxilla,  occurs  most  frequently  in  the  aged; 
however,  it  does  occur  in  the  young  adult.  That  very  intimate  relations 
frequently  exist  between  the  teeth  and  the  maxillary  sinus  is  a  fact  that  one 

1  Zue  Morphologic  des  Sinus  Maxillaris,  Stuttgart,  1878. 


MAXILLARY  SINUS-TEETH  RELATIONS 


FIG.   86. — A  dissection  showing  the  relations  of  the  permanent  teeth  to  the  sinus  maxillaris.     (Com- 
pare with  Fig.  87.) 


\       Fossa  cctrr.inu, 


FIG.  87. — A  dissection  showing  the  relations  of  the  permanent  teeth  to  the  sinus  maxillaris. 
Note  that  the  first  molar  and  the  two  premolars  are  not  in  intimate  relationship  to  the  floor  of  the 
maxillary  sinus.  Note  the  deep  canine  fossa  and  the  emergence  of  a  perforator  pushed  from  the 
inferior  meatus,  escaping  the  maxillary  sinus  altogether  (see  page  114). 


H4  .  THK  MAXILLARY  SINUS 

should  be  cognizant  of.  However,  the  writer  believes  that  these  intimate 
relations  have  been  exaggerated  by  some  authors.  Some  clinicians  hold 
to  the  belief  that  more  cases  of  dental  trouble  are  due  to  maxillary  sinus 
disease  than  the  reverse. 

The  number  of  teeth  that  bear  a  direct  relation  to  the  sinus  is  neces- 
sarily inconstant.  In  exceptional  cases  when  the  cavity  of  the  maxillary 
sinus  is  very  large — especially  in  the  line  of  the  ventrosuperior  diagonal — 
all  of  the  teeth  of  the  true  maxilla  may  be  in  relation  to  the  floor  of  the 
sinus.  It  is,  however,  only  an  occasional  occurrence  to  have  the  canine 
tooth  in  direct  relation  to  the  sinus.  In  a  certain  number  of  cases  the 
first  premolar  tooth  bears  a  direct  relation  to  the  cavity  and  in  a  slightly 


FIG.  88.  FIG.  88/1. 

FIG.   88. — From  an  old  person.     Note  the  atrophy  of  the  alveolar  process  and  the  projection  of  the 

remaining  tooth  into  the  lumen  of  the  maxillary  sinus. 

FIG.   88 A. — From  a  young  adult.      Note  that  despite  a  thick  alveolar  process  the  roots  of  the  molar 
teeth  project  into  the  maxillary  sinus. 

larger  percentage  the  second  premolar  bears  a  similar  relationship.  The 
three  most  constant  teeth,  however,  in  intimate  and  vital  relationship  with 
the  floor  of  the  maxillary  sinus  are  the  molars,  and  when  the  sinus  is  small 
the  first  molar  must  be  omitted  in  this  relationship. 

It  is  a  fairly  safe  rule  to  follow  when  the  canine  fossa  (fossa  canina) 
and  the  lateral  nasal  wall  are  simultaneously  approximated  at  the  expense 
of  the  lumen  of  the  maxillary  sinus,  that  the  canine  and  premolar  teeth  do 
not  bear  a  direct  relation  to  the  maxillary  sinus.  In  such  cases  a  per- 
forator pushed  through  a  premolar-tooth  socket  might  readily  enter  the 
lateral  nasal  wall — even  pass  through  it,  passing  entirely  free  of  the  sinus 
cavity.  Again,  if  the  perforator  were  pushed  through  the  lateral  nasal 
wall,  caudal  to  the  inferior  nasal  concha,  the  instrument  could  readily  be 


MAXILLARY  SINUS  TEETH  RELATIONS 


Ostiwn  nasolacrimale 
Meatu,s  nasi  interior 
Densm  olaris  2H 


Ostinm  matilkrre 
•Sinus  maxi.llaris 
:    Dens  TnolarlslH 


FIG.  89. — A  dissection  looking  into  the  roof  of  the  inferior  nasal  meatus  and  into  the  roof  of  the 
maxillary  sinus.  The  ostia  of  the  nasolacrimal  ducts  and  of  the  maxillary  sinuses  are,  therefore, 
displayed.  Particularly  note  the  impacted  third  molar  teeth  about  to  erupt  into  the  maxillary 

sinuses. 


Dens  Ttiolaris  HL~ 

(deits  seroti7iu,s 
wisdom  tooth) 


PIG.  90. — An  adult  maxilla  with  an  impacted  or  unerupted  third  molar  tooth  exposed  by  the  re- 
moval of  a  superficial  shell  of  bone. 

The  inset  (after  Keith)  shows  "the  manner  in  which  the  development  of  the  maxillary  antrum 
affects  the  size  of  the  palate  and  position  of  the  molar  teeth." 

i  =  posterior  border  of  maxilla  at  birth;  2  =  maxillary  sinus  at  birth;  3  =  maxillary  sinus  of 
adult;  4  =  posterior  border  of  maxilla  of  adult;  5  =  ostium  maxillare;  6  =  deciduous  teeth  at  birth. 


n6 


THE  MAXILLARY  SINUS 


pushed  through  the  soft  structures  of  the  cheek,  unless  the  point  were 
directed  well  superodorsally  (Fig.  87). 

In  the  years  of  adolescence,  as  shown  by  the  studies  of  Keith, 
Schaeffer  and  others,  the  maxillary  sinus  continues  its  pneumatizing  process 
until  it  extends  into  the  various  processes  of  the  maxilla.  Moreover,  as 
the  sinus  expands  dorsalward  the  dorsal  border  of  the  maxilla  which  con- 
tains the  rudiments  of  the  permanent  molar  teeth,  undergoes  rotation 
caudalward,  so  what  was  located  on  the  dorsal  border  ultimately  comes 


FIG.  91. 


PIG.  92. 


FIG.  93. 


to  occupy  a  position  on  the  alveolar  border  of  the  maxilla.  If  for  some 
reason  or  other  growth  and  rotation  are  arrested,  the  third  molar  tooth 
is  left  on  the  dorsal  border  of  the  maxilla  where  it  may  become  impacted 
and  call  for  surgical  attention  (Figs.  89  and  90). 

Ridges,  Crescentic  Projections  and  Septa  on  the  Walls  of  the  Max- 
illary Sinus. — It  is  very  important  to  note  how  frequently  the  walls  of  the 


SEPTA  AND  RECESSES 


117 


sinus  are  found  uneven.  These  irregularities  may  consist  of  mere  ridges  or 
of  different  sized  crescentic  projections.  The  crescentic  projections  have 
been  reported  occasionally  replaced  by  septa  which  completely  divide  the 
sinus  into  two  cavities,  each  having  its  independent  opening  into  the  nasal 
fossa,  but  not  communicating  with  each  other.  The  smaller  ridges  are  of 
little  consequence  and  may  be  omitted  from  further  consideration.  The 


Oin, 


Orn, 


Recess 


Sept. 


Recess 


FIG.  97. 


FIG.  98. 


Recess 


Sept. 


FIG.  99.  FIG.   100. 

FIGS.  97—100. — Drawings  of  specimens  showing  incomplete  septa  with  resultant  recesses  on  the  walls 

of  the  maxillary  sinus. 
Om   =  ostium  maxillare;  Oma   =  ostium  maxillare  accessorium;  Sept   =  septum. 

larger  ridges  and  crescentic  projections,  on  the  other  hand,  tend  to  form 
pockets  and  recesses  of  varying  depth  within  the  cavity.  The  septa, 
when  they  exist,  are  placed  either  cephalocaudally  or  ventrodorsally, 
thus  forming  either  ventral  and  dorsal,  or  caudal  and  cephalic  compart- 
ments, respectively. 

In  an  examination  of  120  adult  maxillary  sinuses  by  the  author,  58  were 
found  in  which  the  walls  showed  minor  ridges  and  large  crescentic  projec- 


n8  THE  MAXILLARY  SINUS 

tions;  the  remaining  62  presented  walls  with  regular  and  even  mucoperi- 
osteal  surfaces.  It  must  be  borne  in  mind  that  in  the  58  positive  sinuses 
quite  a  number  showed  mere  ridges  and  can  be  omitted  from  further  study. 
The  remaining  number  of  the  positive  group  fall,  however,  into  a  very 
important  class  of  specimens.  That  these  crescentic  projections  offer 
almost  insuperable  obstruction  at  times  in  attempting  to  drain  the  maxil- 
lary sinus  through  an  opening  in  the  processus  alveolaris  or  in  the  meatus 
nasi  inferior,  is  an  anatomic  fact  of  which  the  operator  must  be  cognizant 
in  empyemas  that  do  not  yield  readily  to  treatment.  This  was  repeatedly 
demonstrated  in  this  study  by  first  filling  the  sinus  with  a  liquid,  then 
making  an  opening  at  some  point  on  the  processus  alveolaris  and  draining 
what  would  come  away.  If  some  of  the  fluid  was  retained,  allowing  for 
adherence  to  the  mucous  membrane,  the  facial  or  anterior  surface  of 
the  maxilla  was  removed  to  find  where  the  remaining  fluid  was  lodged. 
As  a  rule,  the  portion  of  fluid  was  retained  by  a  recess  or  recesses  on  one  or 
more  of  the  sinus  walls.  At  other  times  a  second  and  even  a  third  opening 
was  made,  either  through  the  alveolar  border,  or  through  the  meatus 
nasi  inferior,  before  the  remaining  fluid  would  come  away.  If  after  re- 
peated attempts  the  fluid  could  not  be  located,  the  ventral  wall  of  the 
cavity  was  removed  to  ascertain  the  reason  for  its  retention  and  the  fact 
was  thus  disclosed  that  repeated  punctures,  in  some  cases,  would  not  reach 
all  of  the  recesses. 

Just  what  these  recesses  mean  in  all  cases  is  difficult  to  say.  Some 
of  them  are,  of  course,  formed  by  elevations  caused  by  tooth  fangs,  but 
these  as  a  rule  are  of  minor  importance  and  only  occasionally  form  deep 
recesses.  Others  are  formed  by  projections  of  mucous  membrane,  which 
may  or  may  not  be  caused  by  crescentic  bone  projections.  Where  excep- 
tionally large  septa  exist  the  maxillary  sinus  probably  developed  from 
two  primary  pouches,  the  intervening  wall  disappearing  in  part  leaving 
the  larger  crescentic  projections  in  the  adult  sinus.  A  double  pouching 
of  the  primitive  maxillary  sinus  was  mentioned  in  a  previous  paragraph 
on  the  development  of  the  cavity  (page  101).  Unequal  resorption  of  the 
bone  during  the  growth  of  the  sinus  is  doubtless  the  chief  cause  for  the 
osseous  projections  on  the  walls  of  the  cavity,  e.g.,  the  sinus  growing  in 
the  direction  of  least  resistance  (Figs.  97,  98,  99  and  100). 

Duplication  of  the  Maxillary  Sinus. — Duplicate  unilateral  maxillary 
sinuses  have  been  recorded  by  Zuckerkandl,  Briihl,  Gruber  and  others. 
The  writer  recently  made  a  number  of  similar  observations.  Zucker- 
handl  found  that  the  superior  and  dorsal  of  the  two  sinuses  communi- 
cated with  the  superior  nasal  meatuses  and  the  inferior  and  ventral  cavity 


SUPERNUMERARY  SINUSES 


119 


with  the  usual  inf undibulum  ethmoidale  of  the  middle  nasal  meatus.  The 
writer  finds  that  the  so-called  additional  or  accessory  maxillary  sinuses  in 
communication  with  the  superior  nasal  meatus  are  of  frequent  occurrence 
and  that  they  are  readily  explained  from  a  genetic  standpoint.  They  are 
clearly  posterior  ethmoid  cells  which  developed  beyond  the  ethmoid  field 
into  the  body  of  the  maxilla,  dorsal  to  the  maxillary  sinus  proper.  Topo- 
graphically, in  the  adult,  they  must,  of  course,  be  considered  maxillary 
sinuses.  Clinically,  too,  their  classification  is  more  maxillary  than  eth- 
moidal,  because  here  one  is  more  concerned  with  the  topography  of  the 
sinus  than  with  its  genetic  history  (Figs.  98  and  101). 


Cunalis  infmorliitaZii 

\          Sinus  maxillou-is 


FIG.  1 01. —A  specimen  with  two  entirely  separate  sinuses  in  the  maxilla.  The  dorsal  sinus 
(sinus  ethmomaxillaris)  communicates  with  the  superior  nasal  meatus  and  the  ventral  one  with  the 
inf  undibulum  ethmoidale  of  the  middle  nasal  meatus  (see  text,  page  118). 

The  aberrant  posterior  ethmoidal  cell  in  question  may  occupy  but  a 
small  portion  of  the  dorsal  and  superior  angle  of  the  body  of  the  maxilla 
or  it  may  pneumatize  more  than  half  of  the  space  more  usually  occupied 
by  the  maxillary  sinus.  The  degree  of  encroachment  on  the  maxillary 
sinus  is,  therefore,  dependent  upon  the  size  of  the  ethmoidal  cell.  Con- 
forming with  the  size  of  the  encroaching  cell,  the  septum  intervening  be- 
tween the  cell  and  the  maxillary  sinus  is  variously  placed ;  now  in  the  vertical 
and  sagittal  plane,  again  in  the  oblique  and  semi-coronal  plane.  The  sep- 
tum may,  therefore,  extend  from  the  alveolar  border  of  the  maxilla  (floor  of 
the  maxillary  sinus)  to  the  infraorbital  wall  (roof  of  the  maxillary  sinus),  or 
from  the  dorsal  wall  of  the  sinus  to  the  roof  of  the  sinus. 


120  THE  MAXILLARY  SINUS 

Clinically,  an  intelligent  appreciation  of  this  not  infrequent  anatomic 
type  of  the  maxillary  field  is  important.  The  dorsal  compartment  of 
the  maxillary  sinus  (aberrant  posterior  ethmoidal  cell),  often  of 
considerable  size,  when  diseased  would  in  all  likelihood  give  the  typical 
symptoms  of  an  involvement  of  the  maxillary  sinus.  The  usual  routes  of 
draining  the  maxillary  sinus  by  way  of  the  inferior  nasal  meatus,  through 
the  alveolus,  or  through  the  canine  fossa,  would,  more  than  likely,  lead 
into  the  unaffected  maxillary  sinus  proper  and  with  negative  findings.  Of 
course,  endonasal  inspection  would  assist  the  operator  in  the  diagnosis, 
as  would  also  the  skiagram. 

These  aberrant  posterior  ethmoidal  cells,  topographically  maxillary, 
practically  always  communicate  with  the  superior  nasal  meatus.  The 
author  observed  one  specimen  in  which  a  cell  in  communication  with  the 
first  supreme  nasal  meatus  extended  into  the  maxilla  and  encroached  upon 
the  maxillary  sinus. 

The  supernumerary  maxillary  sinus  described  by  Brtihl  in  communi- 
cation with  the  inferior  nasal  meatus  is  difficult  of  genetic  explanation 
since  no  paranasal  sinus  develops  from  this  meatus  and  in  the  adult  none 
communicates  with  it.  In  all  likelihood  the  ostium  of  communication  in 
BriihPs  case  was  established  in  a  manner  similar  to  the  formation  of  the 
ostium  maxillare  accessorium  and  the  duplicate  sinus  grew  from  one  of  the 
usual  points  (see  page  101).  Gruber  claims  to  have  found  a  complete 
division  of  the  maxillary  sinus  in  2^  per  cent,  of  cases.  This  is  in  approxi- 
mate agreement  with  the  author's  studies  if  the  posterior  ethmoidal  cells 
which  so  commonly  grow  into  the  maxilla  from  the  dorsal  and  caudal  por- 
tion of  the  superior  nasal  meatus  are  classed  as  maxillary  sinuses.  Indeed, 
it  must  be  recalled  that  the  maxilla  regularly  aids  in  completing  the  osseous 
boundaries  of  certain  ethmoid  cells.  These  are  topographically  ethmo- 
maxillary,  genetically  ethmoidal. 

At  times  the  maxillary  sinus  grows  into  the  hard  palate  by  an  exten- 
sion of  the  alveolar  recess  between  the  plates  of  the  palate  in  the  formation 
of  the  so-called  recessus  palatinus  (Fig.  85).  While  the  latter  recess  is  usu- 
ally in  wide  communication  with  the  maxillary  sinus,  it  is  plausible  to  think 
that  a  narrow  channel  of  communication  may  through  disease  become 
obliterated  and  the  recess  thus  isolated  an  individual  chamber.  One 
readily  sees  how  these  palatine  recesses  may  become  cysts  in  the  hard 
palate.  Meyer1  describes  "a  unique  supernumerary  paranasal  sinus 
directly  above  the  superior  incisors."  He  was  not  certain  of  its  communi- 
cation, and  its  genesis  is  difficult  of  explanation  in  the  absence  of  exact 

1  Jour.  Anat.  and  Phy.,  Vol.  48,  3rd  series,  Vol.  9,  1914. 


SUPERNUMERARY  SINUSES 


121 


knowledge  concerning  its  communication.  Its  total  size  was  1 6  by  13.5  by 
22  mm.  In  this  connection  one  naturally  thinks  of  the  recessus  palatinus 
previously  referred  to  and  to  dentigerous  cysts.  Indeed,  the  Y-shaped 
incisive  foramen  with  the  contained  remnants  of  the  nasopalatine  canals 
at  times  give  rise  to  epithelially-lined  cells  or  cysts.  If  one  recalls  that  the 
nasopalatine  canals  at  one  time  in  the  embryo  connect  the  inferior  nasal 
meatuses  with  the  mouth  cavity  it  is  readily  understood  why  cells  arising 


Sinus  rnfr-aorbi.ta.ll3 


(•Sinus 
Cciitalis  iufraorbitalis 

N.  infrawlitalis 
Sinus  maxillarls 


Orlita, -J 

Fossa.  sacciJMcrimcdis  ---••*' 
Toramtn,  infraorbital^  *-— — 
Suw,s  iTifrcwrftifaZis.. 

Lacrimal  pwtubcrance 


"Jfc^f: 


FIG.  102. — In  A,  the  facial  wall  of  the  maxillary  sinus  has  been  removed  thereby  exposing  the 
median  or  nasal  wall  of  the  sinus.  An  extremely  prominent  lacrimal  proturberance  presents.  More- 
over, it  should  be  noted  that  there  is  a  blindly-ending  recess  in  the  roof  of  the  maxillary  sinus  (sinus 
infraorbitalis)  and  that  the  infraorbital  canal  courses  from  the  infraorbital  wall  to  the  facial  wall  of 
the  maxillary  sinus,  leaving  a  connecting  passageway  over  the  canal  and  contained  nerve  (indicated 
by  the  arrow  in  the  larger  figure). 

The  inset  B,  represents  a  saggital  section  just  lateral  to  the  infraorbital  foramen. 


from  them  may  communicate  in  later  life  with  either  the  inferior  nasal 
meatus  or  the  mouth  cavity.  However,  should  both  extremities  of  the 
nasopalatine  canal  become  obliterated  and  the  intervening  part  remain 
patent,  it  could  readily  give  rise  to  a  cyst.  Of  course,  unusual  and  anoma- 
lous structures  at  times  develop  and  Meyer's  case  may  have  represented 


122  THE  MAXILLARY  SINUS 

a  freakish  accessory  nasal  sinus  which  developed  from  the  inferior  nasal 
meatus.  If  so,  the  case  is  unique  so  far  as  the  writer  knows.1 

The  Size  of  the  Maxillary  Sinus. — The  maxillary  sinus  varies  greatly 
in  size  in  different  individuals.  Moreover,  there  may  be  considerable 
asymmetry  on  the  two  sides  of  the  same  individual.  The  belief  that  all 
old  people  have  large  sinuses  is  very  fallacious,  as  is  also  the  statement  that 
all  females  have  smaller  sinuses  than  males  (tables  C,  D,  and  E). 

The  investigations  of  Zuckerkandl,2  in  which  the  writer  concurs, 
have  shown  that  enlargement  of  the  maxillary  sinus  is  produced  by: 

(a)  Hollowing  out  of  the  processus  alveolaris  of  the  maxilla  (recessus 
alveolaris)  (Fig.  85). 

(6)  Excavation  of  the  floor  of  the  nasal  fossa  by  a  pushing  of  the 
recessus  alveolaris  between  the  plates  of  the  palatum  durum  (recessus 
palatinus)  (Fig.  85). 

(c)  Extension  of  the  maxillary  sinus  into  the  frontal  process  of  the 
maxilla  (recessus  infraorbitalis)3  (Fig.  175). 

(d)  Hollowing   out   of    the   processus  zygomaticus  of  the  maxilla 
(recessus  zygomaticus) . 

(e)  Extension  to,  and  appropriation  of  an  air  cell  within  the  processus 
orbitalis  of  the  palate  bone. 

To  these  should  be  added,  according  to  the  author's  findings:4 

(/")  Extreme  hollowing  out  of  the  body  of  the  maxilla  in  all  directions, 
thus  causing  the  sinus  walls  to  be  thin  and  the  recesses  all  markedly  de- 
veloped (Fig.  174). 

(g)  The  rarer  condition  in  which  the  lateral  nasal  wall  is  bulging 
toward  the  cavum  nasi. 

(h)  The  extension  of  the  recessus  zygomaticus  of  the  sinus  maxillaris 
into  the  maxillary  border  of  the  zygomatic  bone. 

The  sinus  is  made  smaller,  on  the  other  hand,  by: 

(a)  Deficient  absorption  of  the  cancellated  bone  on  the  floor  of  the 
sinus. 

1  Since  concluding  the  above  discussion  the  author  observed  a  specimen  in  which  a  goodly  sized 
epithelially-lined  cavity  existed  in  the  line  of  the  original  nasopalatine  canal.     It  was  a  bl  nd  cavity 
and  communicated  neither  with  the  buccal  cavity  nor  the  nasal  fossa.     Careful  study  of  it  strongly 
indicated  that  it  was  a  remnant  or  persistent  portion  of  the  embryonic  nasopalatine  canal. 

2  Anatomic  der  Nasenhohle,  Leipzig,  1893. 

3  The  term  'recessus  prelacrimalis"  is,  however,  more  applicable  for  this  recess.     The  term  ''reces- 
sus infraorbitalis"  should  be  retained  for  the  occasional  extension  of  the  maxillary  sinus  into  the 
infraorbital  wall  of  the  maxilla  (see  Fig.  102).  '  Indeed,  the  term  ''recessus  frontalis"  is  more  suggestive ; 
however,  is  liable  to  be  confused  with  the  recessus  frontalis  of  the  middle  nasal  meatus. 

1  Schaeffer:  The  Sinus  Maxillaris  and  Its  Relations  in  the  Embryo,  Child  and  Adult  Man,  Amer. 
Jour.  Anat,  Vol.  10,  No.  2,  1910. 


SIZE  OF  SINUS 


123 


(b)  Encroachment  of  the  ventral  wall  of  the  cavity  (Fig.  87). 

(c)  A  deep  fossa  canina  (Fig.  87). 

(d)  Thick  sinus  walls. 

(e)  Excessive  lateral  bulging  of  the  nasal  wall. 
(/")  A  combination  of  the  above  conditions. 

(g)  Imperfect  dentition. 

The  thickness  of  the  sinus  walls  varies  from  5  to  8  mm.  and  down  to 
that  of  a  papery  delicacy.  The  statement  that  all  large  cavities  have  thin 
walls  and  small  cavities  invariably  thick  walls  does  not  hold  in  all  cases. 
The  smallest  sinus  .measured  in  this  series  had  the  thinnest  walls,  the 
small  size  of  the  cavity  being  in  part  due  to  the  marked  simultaneous 
approximation  of  the  ventral  and  medial  walls. 

The  size  of  the  maxillary  sinus  is  best  determined  by  a  series  of 
measurements,  viz.: 

1.  Dorsocephalic  diagonal. 

2.  Ventrocephalic  diagonal. 

3.  Cephalocaudal   (height). 

4.  Ventrodorsal   (length). 

5.  Mediolateral    (width). 

These  several  measurements  are  determined  thus: 

1.  The  dorsocephalic  diagonal,  from  the  most  dorsal  and  lateral  part 
of  the  sinus  floor  diagonally  across  the  base  or  median  wall  of  the  sinus, 
to  the  most  medial  and  cephalic  part  of  the  recessus  infraorbitalis. 

2.  The  ventrocephalic  diagonal,  from  the  most  ventral  and  medial 
part  of  the  recessus  alveolaris  diagonally  across  the  base  of  the  sinus  to 
the  most  lateral  and  cephalic  point  of  the  cavity. 

3.  The  cephalocaudal,  from  the  roof  or  infraorbital  wall  of  the  sinus 
to  the  sinus  floor  (always  using  uniform  points). 

4.  The  ventrodorsal,  from  the  most  ventral  point  of  the  cavity  mid- 
way between  the  roof  and  the  floor,  to  the  dorsal  wall. 

5.  The  mediolateral,  from  the  base  midway  between  its  most  ventral 
and  dorsal  points  to  the  processus  zygomaticus  of  the  maxilla  (in  some 
cases  this  extends  into  the  maxillary  border  of  the  zygomatic  bone,  due 
to  the  extension  of  the  recessus  zygomaticus  of  the  maxillary  sinus  into 
this  bone). 

The  ventrodorsal  distance  is  especially  affected  by  the  degree  of 
approximation  of  the  ventral  wall  of  the  sinus;  the  cephalocaudal  by  the 
degree  of  pneumatization  of  the  processus  alveolaris  of  the  maxilla;  the 
mediolateral  by  the  degree  of  encroachment  of  the  lateral  nasal  wall; 
the  ventrocephalic  diagonal  by  the  extent  of  the  recessus  alveolaris;  and 


124 


THE  MAXILLARY  SINUS 


the  dorsocephalic  diagonal  by  the  extent  of  the  recessus  infraorbitalis. 
Of  course,  there  are  other  contributing  factors  to  shorten  or  lengthen 
these  distances,  but  these  are  the  primary  factors  especially  affecting  the 
several  measurements. 

In  order  that  the  measurements  of  the  maxillary  sinus  may  be  of 
most  value,  it  is  necessary  to  compare  the  two  sinuses  of  the  same  indi- 
vidual ;  to  compare  them  with  the  respective  sinuses  of  another  individual ; 
also  to  consider  the  age  and  the  sex. 

The  following  tables,  C  and'D,  are  appended  for  comparison  as  indi- 
cated above: 

A  careful  examination  of  tables  C  and  D  shows  conclusively  that 
the  maxillary  sinus  has  a  rather  wide  range  of  variation.  Moreover,  the 
tables  indicate  that,  in  the  adult,  age  does  not  have  any  bearing  on  the 
size  of  the  cavity.  Although  the  maxillary  sinus  averages  slightly  larger 
in  the  male  than  in  the  female,  sex  affects  the  size  of  the  cavity  but  slightly. 

Table  E  indicates  the  variation  range  found  in  the  study  of  a  series 
of  specimens.  It  will  be  noted  that  the  smallest  cavity  is  that  of  an  old 
man  aged  70  years,  while  the  largest  cavity  is  that  of  an  old  man  aged 
77  years.  The  same  table  shows  that  the  cavity  of  a  young  adult,  aged 
21  years,  is  a  close  second  to  the  largest  sinus  found  in  the  entire  series. 

TABLE  C. — MAXILLARY  SINUS 
Male — Measurements  in  Millimeters 


Age                 Side 

Ventrodorsal 

Mediolateral 

Cephalocaudal 

1 

Dorsocephalic 
diagonal 

Ventrocephalic 
diagonal 

right 

26 

15 

20 

3° 

26 

54 

left 

30 

16 

22 

32 

26 

68 

right 

40 

22 

5° 

50 

SO 

left 

35 

24 

35 

45 

So 

*6        < 

right 

32 

32 

40 

40 

38 

ou 

left 

3° 

18 

40 

4i 

4i 

6- 

right 

30 

15 

3° 

33 

30 

U5 

left 

25 

15 

25 

35 

36 

right 

40 

25 

40 

45 

45 

55 

left 

40 

22 

38 

36 

45 

right 

40 

21 

32 

50 

38 

57 

left 

32 

25 

3° 

32 

43 

71 

right 

35 

22 

45 

45 

40 

left 

40 

18 

35 

40 

45 

right 

40 

22 

33 

45 

45 

59 

left 

40 

35 

40 

5° 

45 

70 

right 

30 

30 

35 

4i 

40 

/y 

left 

43 

20 

3° 

4i 

37 

-  f 

right 

3i 

24 

3° 

3° 

38 

left 

32 

25 

35 

40 

40 

SIZE  OF  SINUS 

TABLE  D. — MAXILLARY  SINUS 
Female — Measurements  in  Millimeters 


125 


Age 

Side 

Ventrodorsal 

Mediolateral 

Cephalocaudal 

!Dorsocephalic 
diagonal 

Ventrocephalic 
diagonal 

68       < 

right 

35 

35 

35 

40 

30 

left 

40 

16 

3° 

43 

36 

right 

35 

21 

3° 

40 

40 

52 

left 

35 

24 

28 

38 

45 

right 

40 

25 

30 

60 

42 

S3        ' 

left 

33 

30 

45 

45 

46 

right 

36 

26 

25 

37 

37 

47 

left 

37 

28 

35 

35 

37 

right 

33 

24 

3i 

38 

40 

73 

left 

37 

24 

37 

3° 

42 

right 

33 

17 

30 

35 

40 

5° 

left 

33 

22 

33 

38 

34 

right 

3° 

18 

32 

3° 

35 

35 

left 

30 

21 

3° 

3° 

40 

right 

34 

25 

33 

32 

35 

39 

left 

33 

22 

33 

32 

2^ 

right 

38 

25 

3« 

32 

3* 

72        < 

left                    35 

23 

38 

33 

35 

right                 35 

21 

30 

40 

36 

52        ' 

left                    35 

21 

32 

38 

35 

TABLE  E. — MAXILLARY  SINUS 
Measurements  in  Millimeters 


Age 

Side 

Sex 

V-d 

M-l 

C-c 

D-c  D        V-c  D 

70 

R 

M 

15 

12 

21 

21 

18 

70 

L 

M 

16 

12 

21 

21 

20 

35 

L 

M 

22 

20 

3°        31 

25 

54 

L 

M 

25 

15 

22 

32 

27 

54 

R 

F 

26 

15 

20 

30 

26 

60 

L 

M 

30 

2O 

22 

38 

25 

52 

R 

F 

35 

25 

3° 

37 

38 

59 

L 

M 

40 

22 

32 

35 

45 

21 

R 

M 

46 

33 

26 

5° 

50 

77       L        M 

47        40        50        57 

60 

The  following  may  be  given  as  average  measurements  of  the  adult 
maxillary  sinus,  based  on  the  measurements  of  150  specimens: 

1.  Dorsocephalic  diagonal 38.0  mm. 

2.  Ventrocephalic  diagonal 38. 5  mm. 

3.  Cephalocaudal 33 .  o  mm. 

4.  Ventrodorsal 34 -Q  mm. 

5.  Mediolateral 23 .  o  mm. 


126 


THE  MAXILLARY  SINUS 


Due  to  the  great  differences  in  the  several  measurements,  the  capac- 
ity of  the  sinus  in  different  individuals  must  also  differ.  The  range  in 
capacity,  of  the  sinuses  studied  to  ascertain  this  fact,  was  from  9.5  cc.  to 
20  cc.,  with  an  average  of  14.75  cc- 

The  conditions  which  produce  the  varied  differences  in  the  dimen- 
sions of  the  maxillary  sinus  may  be  readily  ascertained.  Take,  for  ex- 
ample, the  following  two  cases  which  show  a  marked  difference  in  the 
mediolateral  plane  with  an  inversion  of  the  other  measurements:,, 


Specimen 

V-d, 
mm. 

M-l, 
mm. 

C-c, 

D-c  D, 

mm. 

V-c  D, 
mm. 

a 

3° 

18 

40 

41 

b  

35 

35 

35 

40 

30 

In  specimen  "a"  the  lateral  nasal  wall  was  markedly  bulging  toward  the 
maxillary  sinus.  In  consequence  of  this  encroachment  the  mediolateral 
distance  was  greatly  lessened.  In  specimen  "b"  the  recessus  alveolaris 
was  poorly  developed,  hence  the  short  ventrocephalic  diagonal  in  com- 
parison with  the  respective  measurement  in  specimen  "a."  These  speci- 
mens show  that  even  though  a  sinus  may  greatly  exceed  another  in  one 
of  its  measurements,  it  may  be  exceeded  in  size  in  its  other  planes. 

Again,  there  may  be  a  great  difference  in  the  ventrodorsal  distance. 
This  means  a  marked  inpushing  or  depression  of  the  ventral  or  facial  wall 
of  the  sinus  on  the  one  hand  and  a  shallow  fossa  canina  with  a  lessened 
encroachment  on  the  other.  Thus: 


Specimen 

V-d, 
mm. 

M-l, 
mm. 

mm. 

D-c  D, 

mm. 

V-c  D, 

mm. 

c  25 

15           25 

35 

36 

d...                        43         20         30 

41 

37 

If  the  body  of  the  maxilla  is  pneumatized  to  a  marked  degree  in  all 
directions  the  measurements  will  be  correspondingly  lengthened.  When 
the  hollowing  out  process  has  not  been  carried  far,  and  when  associated 
with  some  of  the  above-mentioned  conditions,  the  measurements  will  be 
markedly  lessened.  Thus: 


Specimen                                   V-d- 
mm. 

M-l, 
mm. 

C-c, 
mm. 

D-c  D, 

mm. 

V-c  D, 

e.  .  .                                                       A? 

60 

f...                                                                                                                          Tft 

MAXILLARY  OSTIUM  127 

These  few  examples  show  how  anatomic  conditions  affect  the  measure- 
ments of  the  maxillary  sinus.  It  appears  reasonable,  therefore,  that,  by 
examination  of  the  ventral  surface  of  the  maxilla  and  the  lateral  nasal 
wall,  the  size  of  the  sinus  may  be  approximately  determined  and  the  teeth 
relations  judged  with  fair  accuracy.  It  does  not  necessarily  follow,  how- 
ever, because  the  ventral  and  median  walls  of  the  sinus  are  closely  ap- 
proximated, that  the  capacity  of  the  maxillary  sinus  is  markedly  lessened. 
Such  sinuses  may  have  marked  infraorbital  recesses  and  the  processus 
alveolaris  may  be  hollowed  out  toward  its  dorsal  termination.  In  this 
manner  compensation  may  be  made  for  the  marked  encroachment  of  the 
ventral  and  median  walls  of  the  sinus.  It  remains,  however,  that  in  the 
vast  majority  of  cases  where  these  walls  are  simulatneously  bulging  in 
the  cavity  the  sinus  is  correspondingly  reduced  in  size  and  the  canine 
and  premolar  teeth  not  in  direct  relation  to  the  sinus. 

The  Maxillary  Ostium  (ostium  maxillare). — The  primitive  maxillary 
pouch  is  in  relationship  with  the  processus  uncinatus,  the  infundibulum 
ethmoidale,  the  hiatus  semilunaris,  and  the  bulla  ethmoidalis.  The  location 
of  the  maxillary  ostium  of  the  adult  corresponds  to  the  place  of  the 
primitive  maxillary  pouch.  The  pouch  gradually  develops  into  the 
pyramidal-shaped  cavity  of  the  adult,  leaving  the  place  of  communication 
with  the  infundibulum  ethmoidale  at  the  point  of  primary  evagination. 
It  is,  therefore,  obvious  that  the  above  structures,  which  in  the  embryo 
bore  so  close  a  relation  to  the  anlage  of  the  maxillary  sinus,  must  bear 
even  more  important  relations  to  the  maxillary  ostium  of  the  adult 
sinus.  It  is,  therefore,  essential  to  recall  the  regional  anatomy  of  the 
communication  of  the  maxillary  sinus  with  the  nasal  fossa. 

On  raising  or  removing  the  middle  nasal  concha,  in  the  adult,  a 
rounded  elevation — the  bulla  ethmoidalis — is  seen.  As  stated  elsewhere, 
the  latter  is  directed  caudally  and  ventrally.  Immediately  beneath  the 
bulla  is  the  well-defined  curved  margin  of  the  processus  uncinatus  of  the 
ethmoid  bone.  Between  these  structures  is  a  narrow  slit  or  semilunar 
cleft — the  hiatus  semilunaris — from  15  to  20  mm.  long.  The  semilunar 
hiatus  is  an  important  opening,  since  it  is  the  communication  between 
the  meatus  nasi  medius  and  the  gutter-like  infundibulum  ethmoidale. 
The  bulla  ethmoidalis  varies  considerably  in  size.  At  times  it  is  feebly 
developed,  again  may  assume  relatively  large  proportions.  The  size  of 
the  bulla  greatly  influences  the  width  of  the  hiatus  semilunaris  (Fig.  161). 

It  is  easy  to  conclude  what  effect  these  conditions  have  on  the  maxil- 
lary ostium  directly  and  on  the  maxillary  sinus  indirectly.  In  some  cases 
the  cleft  of  communication  between  the  maxillary  ostium  and  the  meatus 


128 


THE  MAXILLARY  SINUS 


nasi  medius  is  practically  shut  off,  while  in  the  others  a  freer  communi- 
cation exists.  It  must  be  remembered,  however,  even  though  the  bull 
touches  the  free  margin  of  the  processus  uncinatus  and  thereby  greatly 
narrows  the  hiatus  semilunaris,  that  the  infundibulum  ethmoidale  may  be 
of  average  dimensions.  This  is  an  important  fact  and  must  be  borne  in 
mind  when  considering  the  fronto-maxillary  relations  and  the  possibility 
of  drainage  from  the  frontal  region  into  the  maxillary  sinus  (see  page  160). 
The  processus  uncinatus  with  its  covering  of  mucous  membrane  pro- 
jects inferiorly  and  dorsally.  By  its  free  superior  border  it  forms  the 
caudal  boundary  of  the  hiatus  semilunaris.  This  process  not  infrequently 


PIG.  103. — A  dissection  with  the  medial  or  nasal  wall  of  the  maxillary  sinus  exposed  from  the 
sinus  side.  Note  especially  the  large  and  elongated  ostium  maxillare  and  its  intimate  relation  to  the 
frontal  sinus.  Obviously  in  such  cases  the  frontal  sinus  drains  almost  wholly  into  the  maxillary 
sinus  (see  text,  page  160). 

terminates  dorsally  in  what  may  be  termed  two  roots :  The  inferior  root 
passes  toward  the  cephalic  edge  of  the  concha  nasalis  inferior,  while  the 
superior  root  curves  superiorly  behind  the  dorsal  termination  of  thebulla 
ethmoidalis  and  causes  the  infundibulum  ethmoidale  to  end  in  a  pocket 
(Fig.  127).  This  fact  is  of  extreme  importance  because  the  pocket  is  so 
situated  that  it  will  direct  fluid  or  infectious  materials  coming  to  the  dorsal 
end  of  the  infundibulum  ethmoidale  into  the  maxillary  sinus,  via  the  maxil- 
lary ostium  which  is  in  the  immediate  location. 

The  infundibulum  ethmoidale  is  a  groove  or  gutter  situated  upon  the 
lateral  nasal  wall.     It  is  bounded  cephalically  by  the  caudal  surface  of 


DUPLICATION  OF  MAXILLARY  OSTIUM 


I29 


the  bulla  ethmoidalis  throughout  the  greater  part  of  its  extent,  save  ven- 
trally  and  superiorly  where  the  bulla  is  replaced  by  some  anterior  eth- 
moidal  cells.  The  caudal  and  mesial  boundary  of  the  groove  is  formed  by 
the  lateral  surface  of  the  processus  uncinatus.  The  infundibulum  ethmoid- 
ale  communicates  with  the  meatus  nasi  medius  through  the  hiatus  semi- 
lunaris and,  as  stated  elsewhere,  either  ends  in  a  pocket  or  loses  its  depth 
gradually  by  merging  with  the  meatus  nasi  medius  proper  (Fig.  125). 
The  cephalic  and  ventral  end  of  the  infundibulum  may  terminate  blindly, 
dilate  into  an  air  cell,  or  be  continuous  with  the  nasofrontal  duct.  The 
lateral  wall  of  the  infundibulum  is  formed  partly  by  mucous  membrane. 
The  depth  of  the  gutter-like  infundibulum  ethmoidale,  i.e.,  the  distance 
from  the  free  border  of  the  processus  uncinatus  to  the  floor  of  the  groove, 
varies  from  i  to  12  mm.,  with  an  approximate  average  of  5  mm. 

The  maxillary  sinus  communicates  indirectly  with  the  meatus  nasi 
medius  by  means  of  a  series  of  openings — (i)  the  maxillary  ostium  which 
pierces  the  superior  and  ventral  part  of  the  base  of  the  sinus  to  open  into 
(2)  the  infundibulum  ethmoidale,  thence  via  (3)  the  hiatus  semilunaris 
into  the  meatus  nasi  medius.  It  must  be  clearly  kept  in  mind  that  the 
ostium  is  located  in  the  superior  part  of  the  sinus  and  that  it  opens  into 
the  infundibulum  ethmoidale  and  not  into  the  hiatus  semilunaris,  as 
many  writers  say.  The  maxillary  ostium  is  located  either  in  the  most 
dependent  part  of  the  infundibulum  or  in  the  lateral  wall  of  this  channel, 
and  varies  from  i  to  12  mm.  in  distance  from  the  hiatus  semilunaris. 
The  distance  is  dependent  upon  the  width  of  the  processus  uncinatus 
and  the  resultant  depth  of  the  infundibulum  ethmoidale  at  this  point. 

The  maxillary  ostium  may  be  round,  but  as  a  rule  is  either  oval  or 
elliptical.  In  a  series  of  no  cases  examined  by  the  writer  it  had  a  great 
range  of  dimensions,  varying  from  i  to  22  mm.  in  length  and  from  i  to 
6  mm.  in  width.  In  cases  where  the  ostium  reaches  considerable  size  it 
may  entirely  replace  the  lateral  wall  or  floor  of  the  infundibulum  eth- 
moidale, thus  forming  a  long  slit-like  communication  between  the  maxil- 
lary sinus  and  the  infundibulum  ethmoidale  (Figs.  77  and  103). 

Duplication  of  the  Maxillary  Ostium.— In  a  previous  paragraph 
mention  was  made  of  the  double  pouching  of  the  primary  maxillary  sinus. 
Distal  fusion  of  two  pouches  would  leave  the  points  of  evagination  as  the 
adult  ostia  maxillaria,  and  the  cavity  proper  would  appear  as  a  single 
chamber.  Most  duplications  of  the  ostium  maxillare  proprius  are,  how- 
ever, doubtless  caused  in  a  manner  similar  to  the  establishment  of  the 
ostium  maxillare  accessorium;  that  is,  by  the  attenuation  and  ultimate 
rupture  of  the  mucous  membrane  in  the  neighborhood  (undefended  region 


130  THE  MAXILLARY  SINUS 

of  the  middle  nasal  meatus,  page  92).  Disease  may  be  the  underlying 
factor  in  some  instances.  The  duplicated  maxillary  ostium  is  always 
located  dorsal  to  the  regular  aperture  and  in  the  dorsal  end  of  the  infundi- 
bulum  ethmoidale.  It  varies  much  in  size. 

The  Accessory  Maxillary  Ostium  (ostium  maxillare  accessorium). — 
The  accessory  maxillary  ostium  is,  as  a  rule,  situated  in  the  membranous 
portion  of  the  lateral  wall  of  the  middle  meatus,  a  short  distance  above  the 
cephalic  and  attached  border  of  the  inferior  nasal  concha  at  about  the 
junction  of  its  middle  and  posterior  thirds.  In  some  instances  it  is  located 
immediately  dorsal  to  the  infundibulum  ethmoidale — occasionally  extend- 
ing into  the  latter.  The  accessory  ostium  is  usually  single,  but  may  be 
duplicated.  Rarely  three  accessory  apertures  are  present  in  this  portion 
of  the  middle  meatus.  The  aperture  must  not  be  confused  with  the 
duplication  of  the  maxillary  ostium  previously  referred  to. 

Nathaniel  Highmore,  who  apparently  was  the  first  anatomist  to 
describe  the  maxillary  sinus,  does  not  mention  the  accessory  ostium. 
Giraldes  in  100  cadavers  found  it  "acht  bis  zehn  Mai."  Zuckerkandl 
reports  it  present  "in  jedem  neunten  bis  zehnten  Falle."  Chiari  and 
Hajek  found  an  accessory  ostium  in  every  fifth  case.  Turner  found  it 
four  times  in  nine  dissections.  The  fourth  annual  report  of  the  committee 
of  collective  investigation  of  the  Anatomical  Society  of  Great  Britain 
and  Ireland  states  that  in  an  examination  of  152  specimens  17.6  per  cent, 
showed  accessory  maxillary  ostia.  Warren  B.  Davis1  in  an  examination  of 
114  lateral  nasal  walls  from  cases  between  4  and  24  years  of  age  reports 
accessory  ostia  in  15  per  cent.;  moreover,  reports  one  instance  in  a  child 
just  past  four  years  of  age.  The  frequence  of  occurrence  as  reported  by 
Davis  can  hardly  be  compared  with  other  reports  since  accessory  ostia  are 
not  common  before  the  fifteenth  year.  In  a  former  paper2  the  writer 
reported  the  accessory  maxillary  ostium  present  35  times  out  of  80  adult 
specimens  examined,  a  percentage  of  43.75.  Three  of  the  specimens  had 
two  accessory  ostia.  In  another  study3  of  125  adult  specimens  the  writer 
reported  accessory  ostia  in  42.4  per  cent,  of  cases,  three  of  the  specimens 
presenting  two  such  apertures.  In  a  third  series,  not  previously  reported, 
of  90  adult  specimens,  the  writer  found  37  per  cent,  with  accessory  ostia. 
J.  A.  Giraldes4  was  apparently  the  first  to  consider  this  opening  from 
a  developmental  point  of  view.  He  came  to  the  conclusion  "dass  in  alien 

^'asal  Accessory  Sinuses,  Philadelphia,  1914. 

2  Schaeffer:  Amer.  Jour.  Anatomy,  Vol.  10,  1910. 

3  Schaeffer:  The  Ostium  Maxillare  Accessorium,  Twenty-sixth  Session  American  Association  of 
Anatomists,  December,  1910. 

4  Archiv  f.  path.  Anat.  und  Physiologic  und  f.  klinische  Medicin,  Bd.  9,  1856. 


ACCESSORY  MAXILLARY  OSTIUM  131 

Fallen,  wo  diese  abnorme  Oeffnung  besteht  sie  immer  das  Product  eines 
pathologischen  Vorganges  und  durch  eine  wirkliche  Perforation  zu  Stande 
gekommen  ist."  He  considered  the  aperture  much  less  common  than  it  is, 
thinking  it  present  in  only  8  or  10  per  cent,  of  instances.  Giraldes  bases 
his  pathologic  theory  on  the  fact  that  he  had  the  privilege  of  following  the 
"Entwicklungsphasen  von  der  Verdunnung  der  Schleimhaut  des  Ganges 
bis  zur  volstandigen  Durchbohrung."  Zuckerkandl  corroborates  the 


FIG.   i 08.  FIG.   109. 

FIGS.  104-109. — Diagrams  of  the  lateral'nasal  wall  with  the  concha  nasalis  media  partly  cut  away. 
Note  the  positions  and  relative  sizes  of  the  ostium  maxillare  accessorium,  indicated  by  the  deep  black 
circles.  See  text,  page  130. 

thinning  of  the  mucous  membrane,  but  does  not  hold  to  the  pathologic 
theory.  The  latter  author  has  seen  some  cases  where  an  accessory  aper- 
ture was  caused  by  the  gradual  wearing  of  a  "zugespitzer  Hakenfortsatz 
der  Nasenscheidewand,"  which  finally  resulted  in  an  opening  on  the 
lateral  wall  of  the  middle  meatus. 

While  some  accessory  apertures  are  obviously  due  to  a  pathologic 
process  as  suggested  by  Giraldes,  and  others  caused  in  a  mechanical 
manner  by  spurs  on  the  nasal  septum  as  suggested  by  Zuckerkandl,  we 


I3 2  THE  MAXILLARY  SINUS 

must  certainly  look  elsewhere  in  most  cases  for  the  genesis  of  this  very 
common  aperture. 

The  author  agrees  that  there  is  a  thinning  of  the  mucous  membrane 
in  the  position  of  the  accessory  maxillary  ostium,  but  believes  the  explana- 
tion for  this  is  found  in  the  development  of  the  maxillary  sinus.  In 
the  fetus  and  infancy  the  walls  of  the  sinus  are  relatively  thick.  The  sinus 
cavity  increases  by  the  simultaneous  growth  of  the  sac  and  the  resorption 
of  surrounding  tissue,  these  processes  taking  place  para  passu  with  the 
growth  of  the  face.  In  this  manner  the  sinus  walls  become  thinner  and 
thinner  up  to  a  limit  as  age  advances.  The  thinning  apparently  progresses 
unevenly,  as  is  evidenced  by  the  very  uneven  walls  of  many  adult  cavities. 
On  the  base  or  median  wall  of  the  cavity  there  is  an  area  that  is  in  time 
composed  merely  of  two  layers  of  abutting  mucous  membrane:  one  the 
mucous  membrane  of  the  middle  meatus,  the  other  the  mucous  membrane 
of  the  maxillary  sinus.  These  two  layers  with  no  intervening  bone  (the 
undefended  area,  Fig.  73)  offer  very  little  resistance  to  the  growing 
maxillary  cavity.  In  time  they  become  so  thinned  out  and  attenuated 
that  ultimately  an  opening  is  formed,  thereby  establishing  the  ostium 
maxillare  accessorium.  This  process  reminds  one  of  the  early  thinning 
and  attenuation  and  ultimate  rupture  of  the  two  layers  of  abutting  epi- 
thelium— the  bucconasal  membranes — in  the  establishment  of  the  primi- 
tive choanae  (page  9). 

If  the  above  hypothesis  as  to  the  genesis  of  the  ostium  maxillare 
accessorium  is  well  grounded  one  would  not  expect  to  find  the  aperture  in 
fetuses  or  in  young  infants.  Indeed,  one  would  not  expect  the  incidence 
of  occurrence  to  be  frequent  before  the  fifteenth  year;  that  is,  when  the 
maxillary  sinus  passes  into  the  adult  stage.  Moreover,  one  would  look  for 
its  appearance,  especially  in  the  adult,  after  the  walls  of  the  maxillary  sinus 
have  been  sufficiently  thinned  out  by  the  enlargement  of  the  cavity.  In 
support  of  the  above  the  writer  has  been  unable  to  find  an  accessory  maxil- 
lary ostium  in  the  fetus  and  in  the  young  child,  but  found  it  very  frequently 
between  the  ages  of  13  and  90  years.  Symington1  says:  "In  children 
I  have  never  found  more  than  one  aperture,  viz.,  that  in  the  infundi- 
bulum."  Davis,2  on  the  contrary,  found  an  accessory  opening  between 
the  fourth  and  fifth  year.3 

1  The  Anatomy  of  the  Child,  Edinburgh,  1887. 

2  Loc.  cit. 

3  Since  the  completion  of  the  manuscript  on  the  maxillary  sinus  the  author  observed  in  a  post- 
mortem on  a  child  aged  1 1  years  a  large  bilateral  accessory  maxillary  ostium.     Careful  examination 
showed  the  mucous  membrane  of  the  nasal  fossae  and  paranasal  sinuses  to  be  in  a  good  state  of  health 
(Fig.  153). 


CONCLUDING  CONSIDERATIONS  133 

The  writer  has,  therefore,  come  to  the  conclusion  that  the  ostium 
maxillare  accessorium  is,  in  most  instances,  established  by  the  developing 
maxillary  sinus;  the  growth  of  the  sinus  causing  the  two  layers  of  abutting 
mucous  membrane  to  become  thinned  and  attenuated,  resulting  ulti- 
mately in  an  additional  aperture  in  very  many  adult  noses.  Some  of 
the  accessory  ostia  are,  doubtless,  due  to  a  pathologic  process,  and  others 
produced  in  a  mechanical  manner  by  septal  spurs.  It  is,  of  course,  diffi- 
cult to  give  the  exact  percentages  in  the  classification  of  causes.  Indeed, 
it  matters  little.  The  fact  remains  that  the  accessory  maxillary  ostium,  a 
direct  communication  between  the  maxillary  sinus  and  the  middle  nasal 
meatus,  is  of  very  frequent  occurrence,  often  of  goodly  size  and  more 
advantageously  placed  as  a  drainage  and  exploring  point  of  the  maxillary 
sinus  than  is  the  regular  maxillary  ostium  which  is  located  farther  cephal- 
ically  and  in  the  depth  of  the  narrow  infundibulum  ethmoidale.  The 
writer  would  urge  that  operators  utilize  this  accessory  ostium  more  fre- 
quently in  irrigations  of  the  maxillary  sinus,  moreover  would  point  out 
that  the  incidence  of  occurrence,  as  given  by  Giraldes  and  so  commonly 
referred  to  in  text-books,  is  archaic  and  far  too  low. 

Concluding  Considerations. — Valuable  information  may  be  learned 
of  the  size,  contour  and  relationships  of  the  adult  maxillary  sinuses  by  the 
use  of  the  X-rays.  The  ventrodorsal  (anteroposterior)  skiagram  usually 
clearly  delineates  the  position  of  the  lateral  nasal  walls  and  the  degree  of 
development  of  the  palatal  recess  of  the  maxillary  sinus.  Moreover,  the 
relationship  of  the  sinus  floor  to  the  nasal  floor  is  indicated,  as  is  also  the 
degree  of  pneumatization  of  the  alveolar  process  (alveolar  recess  of  the 
maxillary  sinus).  Such  information  is,  doubtless,  of  some  value  in  antici- 
pation of  operative  procedures,  either  by  the  endonasal,  alveolar,  or  canine 
fossa  approaches.  Inspection  itself  not  infrequently  gives  the  experienced 
observer  a  fairly  definite  clue  as  to  the  type  of  maxillary  sinus  before  him. 
However,  the  skiagram  is  an  invaluable  supplement  to  inspection.  As 
mentioned  elsewhere  (page  114),  the  simultaneous  approximation  of 
the  medial  (lateral  nasal  wall)  and  ventral  (facial)  walls  of  the  maxillary 
sinus  almost  always  precludes  the  possibility  of  a  palatal  recess  and  of  an 
alveolar  recess  in  the  ventral  third  of  the  alveolus.  A  deep  canine  fossa 
and  a  lateral  bulging  of  the  lateral  nasal  wall  are,  of  course,  readily  deter- 
mined by  inspection ;  the  skiagram  confirming  this  by  showing  a  restricted 
maxillary  sinus  in  its  ventrodorsal  diagonal  and  fewer  teeth  in  true  rela- 
tionship to  the  sinus  floor  (usually  the  second  and  third  molars  only). 

One  must  always  recall  the  possibility  of  dealing  with  a  maxillary 
sinus  incompletely  divided  by  septa  into  sub-compartments  and  that  some 


134 


THE  MAXILLARY  SINUS 


of  these  may  be  of  considerable  depth.  Moreover,  that  the  compartment 
opened  into  may  not  establish  drainage  for  the  entire  sinus.  Indeed,  the 
infection  may  be  in  a  posterior  ethmoidal  cell  which  has  pneumatized  a 
goodly  portion  of  the  body  of  the  maxilla.  In  most  cases  the  normal  max- 
illary sinus  would  be  explored,  with  negative  results  (see  page  118,  Figs. 
98  and  101). 

The  location  of  the  ostium  of  the  maxillary  sinus,  in  the  depth  of 
the  ethmoidal  infundibulum,  would  seem  to  preclude  the  possibility  of 
exploring  the  maxillary  sinus  through  its  normal  aperture.  In  this  con- 
nection it  is  well  to  recall  the  structures  in  relation  to  the  maxillary  osti- 
um; that  is,  the  ethmoidal  bulla,  the  uncinate  process,  the  semilunar 
hiatus,  and  the  ethmoidal  infundibulum.  The  bulla  when  large  practi- 
cally shuts  off  the  semilunar  hiatus  or  entrance  into  the  infundibulum. 
An  examination  of  a  large  series  of  specimens  leads  the  author  to  believe 
that  it  is  impossible  clinically  in  the  vast  majority  of  cases  to  sound  the 
maxillary  sinus  through  its  normal  ostium  (Figs.  128  and  197).  This 
conclusion  based  upon  anatomic  facts  is  in  conformity  with  the  clinical 
findings  of  Cryer,1  Skillern2  and  many  others.  In  those  cases  where 
successful  sounding  of  the  maxillary  sinus  through  the  normal  aperture  is 
reported  it  is  more  than  likely  that  an  artificial  opening  was  made  into 
the  maxillary  sinus  through  the  undefended  floor  and  lateral  wall  of  the 
ethmoidal  infundibulum.  It  is  only  fair  to  state,  however,  that  at  times 
the  ethmoidal  bulla  is  small  and  the  uncinate  process  narrow  and  probably 
turned  nasalward  with  a  resultant  shallow  and  more  or  less  wide-mouthed 
ethmoidal  infundibulum  (Fig.  125).  It  is  in  such  cases  that  the  operator 
succeeds  in  exploring  or  sounding  the  maxillary  sinus  through  its  normal 
aperture — the  ostium  maxillare. 

Perforation  of  the  lateral  wall  of  the  inferior  nasal  meatus  for  purposes 
of  exploring  or  medicating  the  maxillary  sinus  seems  to  be  the  preferred 
route  by  clinicians.  One  must,  however,  always  bear  in  mind  that  the 
floor  of  the  maxillary  sinus  is  in  the  majority  of  cases  at  a  level  inferior 
to  that  of  the  inferior  nasal  meatus  and  that  an  artificial  aperture  by  way 
of  the  inferior  nasal  meatus  does  not  give  the  most  dependent  drainage 
for  the  maxillary  sinus. 

The  frequency  of  the  accessory  maxillary  ostium  connecting  the 
middle  nasal  meatus  and  the  maxillary  sinus  directly  should  not  be  for- 
gotten when  attempting  to  sound  the  sinus  by  way  of  normal  apertures 

1  Internal  Anatomy  of  the  Face,  Philadelphia  and  New  York,  1916. 

2  The  Catarrhal  and  Suppurative  Diseases  of  the  Accessory  Sinuses  of  the  Nose,  Philadelphia 
and  London,  1916. 


CONCLUDING  CONSIDERATIONS  135 

(see  page  130).  The  accessory  aperture  is  frequently  of  goodly  size  and 
is  probed  with  much  greater  ease  than  is  the  constant  aperture  in  the 
depth  of  the  ethmoidal  infundibulum. 

Profile  skiagrams  of  the  maxillary  sinus  are  frequently  confusing  in 
that  it  is  difficult  in  the  healthy  state  to  distinguish  between  the  right  and 
left  sinuses  in  the  picture.  The  ventrodorsal  view  is  to  be  preferred. 

When  subjecting  the  maxillary  sinus,  filled  with  fluid,  to  pressure  the 
undefended  part  of  its  medial  wall  (pars  membranacea)  yields  and  bulges 
into  the  middle  nasal  meatus.  Clinically,  it  is  stated  that  such  bulging 
is  almost  always  pathognomonic  of  an  empyema  of  the  sinus  in  which  the 
normal  aperture  is  either  blocked  or,  because  of  its  size  and  faulty  ana- 
tomic location,  leads  to  deficient  drainage. 


IV-THE  FRONTAL  SINUS 


CHAPTER  IV 

THE  PRONTAL  SINUS 

THE  FETAL  STAGE 

The  nasofrontal  region  is  genetically  an  outgrowth  from  the  ventral 
and  cephalic  end  of  the  middle  nasal  meatus  operculated  by  the  middle 
nasal  concha  (middle  turbinated  bone).  The  mucosa  of  this  part  of  the 
middle  meatus  is,  therefore,  the  proton  of  what  subsequently  becomes  the 
recessus  frontalis  (a  term  very  suggestive,  and  to  be  preferred  to  the 
recessus  conchalis  used  by  others)  of  the  middle  nasal  meatus  (early  in 
evidence)  and  derivatives  therefrom.  The  recessus  frontalis  in  turn  is  the 
rudiment  of  the  sinus  frontalis  and  certain  of  the  anterior  group  of  the  cellu- 
Ice  ethmoidales  (also  called  cellulse  fron tales  by  Killian,  Onodi  and  others). 


Frontal  furrows 


FIG.   no. — A  dissection  of  the  frontal  recess  of  a  term  fetus  showing  the  early  frontal  furrows  or  pits; 
e.g.,  rudiments  of  anterior  ethmoidal  cells  and  potential  rudiments  of  the  frontal  sinus.       X  1.5. 

As  early  as  the  end  of  the  third  or  beginning  of  the  fourth  month  of 
embryonic  life,  one  sees  evidence  of  a  beginning  extension  of  the  middle 
nasal  meatus  in  a  ventrocephalic  direction.  This  early  extension  is  the 
beginning  of  the  recessus  frontalis,  and  is,  strictly  speaking,  the  first  step  in 
the  formation  of  the  frontal  sinus  and  certain  of  the  anterior  group  of 
ethmoidal  cells.  For  some  time  the  lateral  wall  of  the  recessus  frontalis 
is  even  and  unbroken  and  gives  no  evidence  of  the  later  configuration 
and  complexity  which  characterizes  the  region  in  the  adult  nose.  Coronal 
sections  and  transections  of  the  recessus  frontalis  of  a  4-month  fetus 
show  the  lateral  nasal  plate  of  cartilage  thickened  at  certain  points. 
These  thickened  cartilaginous  areas — the  precursors  of  the  folds  or 

139 


140  THE  FRONTAL  SINUS 

accessory  conchae  which  later  configure  the  lateral  wall  of  the  recessus 
f rontalis — vary  in  number  and  are  for  a  period  low  and  inconspicuous  and 
do  not  throw  the  nasal  mucosa  into  relief. 

Upon  examining  the  recessus  frontalis  in  the  late  fetus,  one  finds  a 
variable  number  of  low  accessory  conchae  on  its  lateral  wall  (Figs.  35  and 
36).  The  folds,  with  the  cartilaginous  skeleton  now  partly  ossified, 
are  at  this  time  sufficiently  developed  to  throw  the  nasal  mucosa  into 
relief.  Between  the  folds  are  found  pits  or  furrows,  the  positive  growth 
or  outpouching  of  which  aids  materially  in  making  more  prominent  the 
folds.  It  is  appropriate  to  speak  of  the  latter  as  accessory  or  hidden 
frontal  folds  or  conchae  and  the  pits  as  frontal  furrows  of  the  middle  nasal 
meatus.  As  mentioned  above,  there  is  no  constancy  in  the  degree  of 
differentiation  and  development  of  the  frontal  folds  and  furrows.  The 
number  varies  from  a  complete  absence  to  four  or  five.  In  some  instances, 
therefore,  the  recessus  frontalis  remains  a  simple  blind  outgrowth  from 
the  middle  nasal  meatus  without  configuration  of  its  lateral  wall  (Fig.  1 1 1 .) 

The  processus  uncinatus  and  the  folds  composing  the  bulla  ethmoid- 
alis  should  likewise,  as  previously  stated,  be  considered  accessory  conchae 
of  the  middle  nasal  meatus  (analogues  and  homologues  of  the  frontal 
conchae),  and  the  infundibulum  ethmoidale  and  the  suprabullar  furrow 
as  accessory  meatuses  or  furrows  of  the  middle  nasal  meatus  (analogues 
and  homologues  of  the  frontal  furrows). 

The  frontal  furrows  or  pits  early  evaginate  and  form  certain  of  the 
anterior  group  of  ethmoidal  cells  or  the  so-called  frontal  cells.  Semi- 
coronal  sections  through  the  recessus  frontalis  show  these  early  cells. 
When  the  latter  cells  are  followed  in  serial  sections  toward  the  recessus 
frontalis,  they  are  shown  to  be  extensions  or  outpouchings  of  the  frontal 
furrows  and  in  communication  with  the  recess  (Figs.  147  and  148).  Some  of 
the  ethmoidal  cells  having  their  genesis  in  frontal  pits  remain  diminutive 
and  ethmoidal  in  topography,  while  others  grow  to  considerable  size  and 
often  develop  beyond  the  confines  of  the  ethmoid  bone. 

It  is  a  well-established  fact  that  the  frontal  sinus  develops  variously: 
(i)  by  a  direct  extension  of  the  whole  recessus  frontalis,  (2)  from  one  or 
more  of  the  anterior  group  of  cellulae  ethmoidales  which  have  their  point 
of  origin  in  frontal  furrows,  and  (3)  occasionally  from  the  ventral  extremity 
of  the  infundibulum  ethmoidale,  either  by  direct  extension  or  from  one  of 
its  cellular  outgrowths.  Indeed,  the  frontal  sinus  is  frequently  unilaterally 
or  bilaterally  present  in  duplicate  or  triplicate,  indicating  a  genesis  from 
more  than  one  of  the  aforementioned  areas.  The  frontal  sinus  is,  embryo- 
logically  speaking,  in  many  instances,  an  anterior  ethmoidal  cell  which 


FETAL  STAGE  141 

has. grown  sufficiently  far  into  the  frontal  region  to  be  topographically  a 
frontal  sinus. 

The  first  evidence  of  the  frontal  sinus  must  not  be  sought  in  the 
frontal  bone,  but  in  the  recessus  frontalis  of  the  middle  nasal  meatus. 
Lack  of  observance  of  this  embryologic  truth  has  led  to  such  statements 
as:  "in  the  newborn  infant  no  trace  of  a  frontal  sinus  is  visible;"  "the 
earliest  sign  of  a  frontal  sinus  is  seen  about  the  end  of  the  first  year  in  the 
form  of  a  shallow  depression;"  "the  frontal  sinus  is  completely  absent  in 
the  newborn  infant."  Poirier  states  that  the  frontal  sinus  is  first  seen 
about  the  end  of  the  second  year.  Tillaux  puts  it  as  late  as  the  twelfth 
year.  Onodi,  Davis,  Schaeffer  and  others  recognize  the  frontal  sinus 
as  such  in  some  instances  early  in  extrauterine  life.  Killian  operated 
upon  a  diseased  frontal  sinus  in  a  child  15  months  old.  As  stated 
before,  the  recessus  frontalis  of  the  middle  nasal  meatus  is  demonstrable 
as  early  as  the  fourth  fetal  month  and  late  in  fetal  life  it  becomes  complex 
by  the  formation  of  the  frontal  furrows  or  pits,  etc.  One  is  not  justified 
as  a  rule  in  the  term  child  to  hazard  an  opinion  as  to  the  specific  point 
from  which  the  sinus  frontalis  will  ultimately  develop.  There  are  ex- 
ceptions to  this  rule:  occasionally  at  birth  the  genetic  point  for  the  sinus 
frontalis  is  obvious;  again,  one  cannot  be  certain  until  the  second  or  third 
year.  The  various  potential  rudiments  (frontal  recess  and  certain  anterior 
ethmoidal  cells,  etc.)  of  the  sinus  are,  however,  far  advanced  by  the  end  of 
fetal  life.  One  must  always  bear  in  mind  that  the  sinus  frontalis  is  genet- 
ically and  topographically  ethmoidal  before  it  is  frontal  and  in  this  sense 
is  conspicuously  present  at  birth  in  all  cases. 

From  the  suprabullar  furrow  develop  most  of  those  anterior  ethmoidal 
cells  which  in  time  honeycomb  the  bulla  ethmoidalis  (Figs.  156,157  and  1 58) . 
Rarely  the  suprabullar  furrow  seems  to  be  the  genetic  point  for  the  sinus 
frontalis.  This  may  be  apparent  only  and  not  the  actual  condition,  since 
the  most  dorsal  and  cephalic  of  the  frontal  pits  and  the  suprabullar  furrow 
are  at  times  continuous  channels.  This  may  lead  to  the  interpretation 
that  the  frontal  sinus  developed  from  the  suprabullar  furrow,  when  in 
reality  it  developed  from  a  frontal  pit  (early  anterior  ethmoidal  cell). 

The  infundibulum  ethmoidale  at  its  ventral  extremity  usually  ends 
blindly  by  forming  one  or  more  anterior  ethmoidal  cells  (infundibular 
cells)  of  variable  size  and  location.  In  the  majority  of  cases  such  cells 
are  lateral  to  the  frontal  recess.  They  may,  however,  grow  far  from  the 
point  of  genesis  and  form  conchal  and  agger  cells  (see  page  221).  Indeed, 
they  may  grow  sufficiently  far  into  the  frontal  region  to  become  frontal 
sinuses.  In  any  event  they  communicate  always  with  the  infundibulum 


I42  THE  FRONTAL  SINUS 

ethmoidale.  The  infundibulum  ethmoidale  and  one  or  other  of  the  frontal 
furrows  or  pits  are  frequently  in  the  same  axis  in  the  fetus  and  at  times  are 
contiguous.  Early  resorption  of  the  intervening  barrier  would  cause 
a  frontal  furrow  and  the  infundibulum  ethmoidale  to  become  continu- 
ous channels,  and  in  the  late  fetus  and  infant,  as  well  as  in  the  adult,  it 
would  be  difficult  to  prove  that  the  channels  were  primitively  discontinu- 
ous. It  would  be  equally  difficult  to  state  the  genetic  point  of  the  frontal 
sinus,  e,g.,  whether  in  the  infundibulum  ethmoidale  or  in  a  frontal  cell. 
It  must,  however,  here  be  pointed  out  that  it  is  unusual  initially  for  the 
infundibulum  ethmoidale  to  be  directly  continuous  with  a  frontal  furrow 
or  pit  (Fig.  127).  Of  course,  one  must  observe  the  embryonic  and  fetal 
nose  at  the  proper  ages  to  see  the  justice  of  this  statement.  Continuity 
of  channels  is,  however,  an  occasional  occurrence.  Furthermore,  the 
adult  nasofrontal  duct  and  the  infundibulum  ethmoidale  are,  strictly 
speaking,  in  the  majority  of  cases,  discontinuous  channels.  The  latter 
is  significant  when  one  recalls  the  careless  statement,  frequently  made 
without  qualification,  that,  in  the  adult,,  the  "  infundibulum  ethmoidale 
is  continued  upward  as  the  nasofrontal  duct  into  the  sinus  frontalis." 

It  will  doubtless  aid  in  making  the  adult  conditions  one  meets  more 
comprehensible  if  here  reference  is  made  to  specific  fetal  conditions. 
In  Fig.  no  the  infundibulum  ethmoidale  is  in  line  with  the  third  frontal 
furrow,  but  not  directly  continuous  with  it.  If  in  this  case  the  frontal 
sinus  should  develop  from  the  anterior  ethmoidal  cell  of  the  first  or  second 
frontal  furrows  or  from  the  frontal  recess  directly,  the  nasofrontal  duct 
of  the  adult  sinus  would  doubtless  communicate  directly  with  the  middle 
nasal  meatus  and  not  with  the  infundibulum  ethmoidale.  If,  on  the 
other  hand,  the  frontal  sinus  should  develop  from  the  cell  of  the  third 
frontal  furrow,  the  nasofrontal  duct  would  be  continued  down  to  the 
infundibulum  ethmoidale,  but  not  be  directly  continuous  with  it,  unless 
the  bridge  of  intervening  tissue  were  absorbed,  as  occasionally  happens. 
A  frontal  sinus  developing  from  the  cell  of  the  third  frontal  furrow  would 
in  all  probability  have  a  tortuous  nasofrontal  duct.  This  would,  of 
course,  depend  largely  upon  the  disposition  and  size  of  the  other  anterior 
ethmoidal  cells. 

In  the  dissection  shown  in  Fig.  35  the  infundibulum  ethmoidale 
and  the  first  frontal  furrow  are  practically  continuous  with  each  other. 
Should  the  frontal  sinus  develop  from  the  first  frontal  furrow  in  such  a 
condition,  the  nasofrontal  duct  would  be  directly  continuous  with  the 
infundibulum  ethmoidale  in  the  adult.  One  must  not  err,  however,  in 
such  a  condition  by  believing  that  the  sinus  frontalis  necessarily  developed 


CHILDHOOD  STAGE 


143 


from  the  infundibulum  ethmoidale.  From  adult  relations  it  would  appear 
as  if  the  latter  interpretation  were  correct;  embryology,  however,  shows 
the  error  of  this  contention.  If  in  the  specimen  shown  in  Fig.  35  the 
frontal  sinus  formation  should  take  place  from  the  cell  of  the  second  frontal 
furrow,  the  nasofrontal  duct  would  be  continued  down  to  the  infundi- 
bulum ethmoidale  at  an  angle,  but  not  be  directly  continuous  with  it. 
In  the  specimen  shown  in  Fig.  in  (from  a  child  aged  14  months)  the 
whole  frontal  recess  is  extending  and  developing  into  the  frontal  sinus. 
In  the  latter  case  the  adult  sinus  would  in  all  probability  have  no  true 
nasofrontal  duct,  but  the  sinus  would  open  directly  into  the  ventral  and 
superior  portion  of  the  middle  nasal  meatus. 

In  a  general  way  one  may  say  that,  when  the  frontal  sinus  develops 
from  an  anterior  ethmoidal  cell,  the  adult  cavity  will  more  frequently 
have  a  nasofrontal  duct — the  tortuosity  of  the  duct  depending  upon  the 
cell  from  which  the  sinus  developed  and  upon  the  degree  of  development 
and  disposition  of  the  neighboring  anterior  ethmoidal  cells.  On  the 
other  hand,  when  the  frontal  sinus  develops  by  a  direct  extension  of  the 
frontal  recess  there  will  in  all  likelihood  be  no  true  nasofrontal  duct. 

THE  CHILDHOOD  STAGE 

The  sinus  frontalis  as  such  may  or  may  not  be  demonstrable  at  birth. 
The  various  potential  rudiments  of  the  sinus  are  far  advanced;  none,  how- 


FIG.  in. — A  dissection  of  the  frontal  recess  illustrating  the  degree  of  development  of  the  frontal 
sinus  in  a  child  aged  14  months.  Note  that  the  whole  frontal  recess  is  expanding  into  the  frontal 
sinus.  X  0.8. 

ever,  topographically  frontal.  As  a  rule,  one  cannot  be  certain  of  the 
actual  frontal  sinus  until  the  sixth  to  the  twelfth  month  of  postfetal  life. 
Notwithstanding,  in  some  newborn  babies  the  frontal  sinus  is  more  pre- 


144 


THE  FRONTAL  SINUS 


cocious  than  in  the  average  and  can  be  determined  with  reasonable  cer- 
tainty at  this  time. 

The  various  outpouchings  from  the  recessus  frontalis  continue  to 
extend  their  boundaries  and  the  one  destined  to  form  the  frontal  sinus 
(if  the  frontal  recess  is  the  source)  ultimately  comes  in  contact  with  the 
horizontal  portion  (pars  orbitalis)  of  the  frontal  bone,  and  up  to  this  time 
the  mucous-membrane  sac  has  a  thin,  compact  bone  matrix.  Extension 
into  the  horizontal  portion  of  the  frontal  bone  now  follows,  thence  between 


,  Sinus  sphenoidalis 
Sinus  frontalis 


Cellulae  ethmoidales 
Ostium  maxiUare- 
Si-nits  maxillaris 


&  a  ecus  lacrimaU* 


FIG.   112. — Photograph  of  a  dissection  of  the  paranasal  sinuses  of  a  child  aged  6  years,  6  months  and 
15  days.      (Dissection  by  Dr.  Warren  B.  Davis.) 

the  tables  of  the  vertical  portion  (squamous  frontalis),  by  the  simul- 
taneous growth  of  the  sinus  and  resorption  of  the  cancellous  bone.  There 
is  a  great  variation  in  growth.  However,  by  the  eighteenth  or  twentieth 
month  the  frontal  sinus  has  "eroded"  into  and  begun  to  ascend  the  vertical 
portion  of  the  frontal  bone,  and  by  the  middle  of  the  third  year  the  cupola 
of  the  sinus  is  above  the  level  of  the  nasion.  It  should  be  here  noted 
that  in  many  instances  the  frontal  sinus  never  invades  far  into  the  vertical 
portion,  but  grows  extensively  into  the  horizontal  portion  of  the  frontal 


CHILDHOOD  STAGE 


145 


bone,  forming  a  large  air  space  (or  spaces)  over  the  orbit.  This  leads  to 
the  erroneous  belief  that  there  is  frequently  an  agenesis  of  the  frontal 
sinus. 

When  the  sinus  first  invades  the  vertical  portion  of  the  frontal  bone, 
it  is  nearer  the  inner  than  the  outer  plate.  This  leads  to  a  thin  dorsal 
wall — almost  wholly  compact  bone — as  opposed  to  a  fairly  thick  ventral 
wall  composed  of  both  compact  and  cancellous  (diploe)  bone.  From  the 
outset,  in  the  invasion  of  the  frontal  bone,  the  frontal  sinuses  vary  in  size 
and  shape  and  are  usually  asymmetrical.  The  septum  frontale  is  seldom 
in  the  mid-sagittal  plane,  save  at  its  base,  ventrally.  It  is,  however,  well 
known  that  a  persistent  metopic  suture  usually  precludes  the  likelihood 
of  development  of  the  sinus  beyond  the  median  plane  (Fig.  66). 

Table  F  gives  the  measurements  in  millimeters  of  the  frontal  sinus 
in  a  series  of  specimens  from  6  months  to  20  years  of  age.  There  is 
a  gradual  increase  in  the  size  of  the  sinus  in  one  diameter  or  another  as 
age  advances.  In  a  general  way,  this  is  true  of  all  measurements.  How- 
ever, in  some  instances  a  certain  diameter  may  lag  far  behind.  Witness, 
for  example,  the  short  cephalocaudal  diameter  and  the  deep  ventrodorsal 
diameter  in  the  17-  to  1 8-year  specimen — a  sinus  of  the  supraorbital  type. 
This  must,  of  course,  not  be  taken  as  indicative  of  the  type  of  sinus  at 

TABLE  F 


Distance  of 

Distance  of 

Measurement 

«; 

Age 

Side 

ostium  fron- 
tale below 
nasion 

cupola  of  sinus 
frontalis 
above  nasion 

Cephalo- 
caudal 

Medio- 
lateral 

Ventro- 
dorsal 

Size  of  os- 
tium frontale 

(height) 

(width) 

(length) 

6—i2  mos. 

R 

4-5 

2  .  o  below 

2.0 

1-5 

3-5 

-5X0.7 

L 

4-5 

i  .  5  below 

2.0 

2.0 

3-5 

•  5X0.4 

1-2  yrs. 

R 

3-° 

2.0 

5-0 

24 

4.0 

0X0.7 

L 

3-5 

1.6 

4-9 

2.6 

5-0 

.6X0.8 

3-4  yrs. 

R 

3-5 

2.0 

5-o 

3-5 

4-5 

.8X0.8 

L 

4.0 

2-5 

7-o 

4.0 

5-5 

.8X0.8 

5-6  yrs. 

R 

5-5 

3-5 

8.0 

3-5 

6.0 

.0X0.7 

L 

4-o 

3-° 

7-0 

3-5 

6.0 

.8X0.8 

7-8  yrs. 

R 

4-o 

9-5 

13.0 

IO.O 

8-5 

.5X0.2 

L 

4.0 

IO.O 

15.0 

IO.O 

7-o 

.7X2.1 

lo-n  yrs. 

R 

4.0 

12.  O 

16  .0 

8.0 

8.0 

3.0X2.0 

L 

6-5 

12.  O 

17.0 

9-c 

5  -5 

3-0X2.5 

13-14  yrs. 

R 

3-o 

7-5 

10  5 

8-5 

IO.O 

4.0X2.0 

L 

4.0 

ii  .0 

15-0 

9.0 

12.5 

3-5X2.0 

14-15  yrs. 

R 

2.0 

16.0 

18.0 

18.0 

II  .0 

3.0X2.0 

L 

3.0 

15-5 

18.5 

20.  o 

II  .0 

3.0X2.0 

17-18  yrs. 

R 

3.0 

4.0 

7-0 

IO.O 

20.0 

3-5X1.5 

L 

6.0 

II  .0 

16.0 

18.0 

16.0 

4.0X2.0 

19  20  yrs. 

R 

2.O 

i  26.0 

28.0 

27.0 

17.0 

9.0X8.0 

L 

2  .  o  above 

28.0 

26.0 

26.0 

16.0 

3  0X2.0 

146  THE  FRONTAL  SINUS 

this  age,  another  specimen  of  the  same  age  might  show  a  totally  different 
series  of  measurements. 

The  further  development  and  variations  in  the  anatomy  of  the  sinus 
frontalis  are  best  considered  in  connection  with  the  adult  stage. 

THE  ADULT  STAGE 

General  Considerations. — It  is  a  well-established  fact  that  the  an- 
atomy of  the  adult  frontal  sinus  varies  greatly — there  being  no  constancy 
in  size,  shape  or  type.  The  sinuses  in  the  same  individual  are  usually 
asymmetrical  and  either  or  both  may  be  present  in  duplicate  or  triplicate. 
The  writer  has,  indeed,  observed  as  many  as  four  frontal  sinuses  on  one 
side,  each  independent  of  another  and  with  its  own  communication  with 
the  nasal  cavity.  Moreover,  there  is  considerable  variation  in  the  manner 
of  communication  of  the  frontal  sinus  with  the  nasal  cavity — a  fact  in 
accord  with  the  varied  embryology.  Agenesis  of  the  sinus  has  also 
been  observed  by  a  number  of  investigators.  All  of  these  variations  are 
of  utmost  importance  to  the  clinician,  and  an  appreciation  of  them  will 
doubtless  aid  in  clearing  up  obscure  cases. 

The  frontal  sinus  of  the  adult  is  seldom  a  simple  chamber.  It  is 
frequently  more  or  less  divided  into  subcompartments  or  recesses  by 
incomplete  bony  partitions.  It  lies  between  the  two  plates  of  the  frontal 
bone  in  both  the  vertical  (squamous  frontalis)  and  horizontal  (pars  orbit- 
alis)  portions  of  the  bone.  Its  ventral  and  thicker  wall  usually  forms  the 
prominence  of  the  forehead  above  the  eyebrows  (the  thickness  varies 
from  i  to  10  mm.).  A  prominent  supraorbital  swelling  (superciliary 
ridge}  must,  however,  not  be  taken  to  mean  an  undoubted  large  frontal  sinus. 
The  prominence  is  very  misleading  at  times  if  thought  to  be  indicative 
of  the  size  of  the  frontal  sinus.  The  dorsal  and  cephalic  wall  separates 
the  frontal  sinus  from  the  frontal  lobe  of  the  brain.  When  the  frontal 
sinus  is  extensively  developed  over  the  orbit  it  is  in  relationship  with  the 
gyri  frontales:  inferior,  medius,  and  superior.  The  caudal  wall  of  the 
sinus  is  in  relationship  with  the  tissues  of  the  orbit  and  in  part  overlies  the 
anterior  ethmoidal  cells.  Indeed,  if  the  frontal  sinus  has  developed  far 
dorsad  between  the  plates  of  the  horizontal  part  of  the  frontal  bone, 
it  will  overlie  the  posterior  ethmoidal  cells  likewise.  The  frontal  sinus 
occasionally  extends  into  the  crista  galli.  The  septum  frontale  is  always 
present;  seldom,  however,  in  the  mid-sagittal  plane  throughout,  and 
according  to  the  author's  specimens  is  very  rarely  perforated,  save  in 
disease.  It  is,  however,  often  of  a  papery  thickness  in  certain  parts. 


ADULT  STAGE 


Size  of  the  Adult  Frontal  Sinus. — Briihl  in  a  study  of  the  frontal  sinus 
found  the  capacity  of  the  combined  sinuses  to  vary  from  6  to  16  cc.  The 
writer's  investigations  show  the  combined  volume  of  the  right  and  left 
frontal  sinuses  to  vary  from  i  cc.  to  45  cc.  The  extremes  in  capacity  repre- 
sent, of  course,  relatively  few  specimens  and  should  not  be  taken  into 
account  in  speaking  of  the  average  measurements.  The  following  table 
(G)  taken  from  the  studies  of  three  writers  gives  the  average  size  in  milli- 
meters of  the  sinus  f rontalis  in  the  different  planes : 

TABLE  G 


Author 

Cephalocaudal 
(height) 

Mediolateral 
(width) 

Ventrodorsal 
(length) 

Boege      ...                 ... 

20.  8 

21   6 

16  I 

Loeb  . 

^.U 

23    O 

Schaeffer 

A  series  of  specimens  taken  at  random  from  a  larger  series  investigated 
by  the  writer  show  variations  in  the  several  diameters  as  follows  (table  H) : 


TABLE  H 


No. 

Cephalocaudal 
(height) 

Mediolateral 
(width) 

Ventrodorsal 
(length) 

R 

L 

R 

L 

R 

L 

I 

26 

30 

3i 

24                       45 

44 

2 

18 

18 

24 

29 

19 

33 

3 

8 

12 

J3 

22 

6 

10 

4 

29 

22 

27                         32 

40 

42 

5 

10 

9 

5                        19 

5 

7 

6 

26 

3° 

16 

21 

35 

40 

7 

16 

20 

20                         35 

27 

36 

8 

J7 

17                                   24                                  30 

20                         37 

Extensive  Pneumatizationsby  the  Frontal  Sinus. — The  writer  recently 
encountered  frontal  sinuses  of  enormous  size,  far  exceeding  Brtihl's  maxi- 
mum. Witness,  for  example,  the  dissection  of  an  adult  male  shown  in 
Fig.  113.  The  skull  has  three  frontal  sinuses,  one  on  the  right  side  and  two 
on  the  left,  in  communication  with  the  frontal  recess  of  the  related  side. 
The  whole  of  the  orbital  (horizontal)  portion  of  the  frontal  bone  is  pneuma- 
tized.  Indeed,  the  frontal  sinuses  are  not  confined  to  the  frontal  bone: 
Laterally  and  dorsally  they  extend  into  the  great  or  temporal  wings  (alae 
magnae)  and  dorsally  and  medially  into  the  small  or  orbital  wings  (alae 
parvae)  of  the  sphenoid  bone.  The  medial  one  of  the  two  left  sinuses 


x48 


THE  FRONTAL  SINUS 


extends  into  the  crista  galli  of  the  ethmoid  bone.  Moreover,  the  sinuses 
extend  into  the  frontal  or  nasal  processes  of  the  maxillae  and  into  the  nasal 
bones.  Numerous  finger-like  projections  of  the  sinuses  have  hollowed 
out  the  frontal  (vertical)  portion  of  the  frontal  bone  to  an  unusual  degree. 
The  total  capacity  of  the  three  frontal  sinuses  represented  in  Fig.  113 
is  38  cc.  Everywhere  the  walls  of  the  sinuses  are  extremely  thin.  The 


PIG.  113. — Skull  from  an  adult  male.  The  frontal  sinuses  in  the  vertical  portion  of  the  frontal 
bone,  in  the  great  wings  of  the  sphenoid,  and  in  the  temporal  bones  are  represented  by  cross-hatching. 
Note  that  there  are  two  sinuses  on  the  left  side  and  one  on  the  right.  The  orbital  extension  of  the 
sinuses  is,  of  course,  not  shown.  The  combined  capacity  of  these  unusually  large  frontal  sinuses  was 
thirty-eight  cubic  centimeters.  (After  J.  P.  S.,  Annals  of  Surgery,  December,  1916.) 

enormous  capacity  of  the  sinuses  in  this  specimen  can  better  be  appreciated 
when  one  recalls  Briihl's  findings  (page  147).  Clinically  it  is  of  importance 
to  appreciate  the  additional  anatomic  relationships  of  the  frontal  sinuses 
in  such  extensive  pneumatizations. 

Even  more  extensive  are  the  frontal  sinuses  illustrated  in  Figs. 
1 14  and  115.  The  dissections  are  from  an  adult  male.  Every  part  of  the 
orbital  (horizontal)  portion  of  the  frontal  bone  is  hollowed  out.  The 


SIZE  OF  SINUS 


149 


intracranial  walls  of  the  frontal  sinuses  are  crowded  bullous-like  toward  the 
anterior  cranial  fossa.  Extensive  and  numerous  finger-like  recesses  of 
the  sinuses  project  variously  into  the  vertical  portion  of  the  frontal  bone 
(Fig.  115).  On  both  sides  the  sinuses  extend  into  the  great  or  temporal 
wings  (alae  magnae)  and  into  the  lesser  wings  (alae  parvae)  of  the"  sphenoid 


Sinus  fronted  is 


FIG.    114. — A  dissection  of  enormously  developed  frontal  sinuses.     The  intracranial  walls  of  the 
sinuses  have  been  removed  (see  text,  page  147). 

bone.  There  is  even  an  extension  bilaterally  into  the  temporal  bones  and 
well  down  to  the  root  of  the  nose  into  the  nasal  bones  and  into  the  frontal 
or  nasal  processes  of  the  maxillae.  In  Fig.  114  the  intracranial  wall 
of  the  sinus  is  removed,  thus  exposing  the  sinuses  in  their  entirety.  It 
is  especially  important  to  note  the  extensive  anatomic  relationships  of  the 
frontal  sinuses  in  this  specimen.  The  two  sinuses  are  markedly  asym- 


1 5o  THE  FRONTAL  SINUS 

metrical.  Many  recesses  and  incomplete  bony  septa  are  present.  The 
capacity  of  the  two  sinuses  (Figs.  114  and  115)  is  45  cc. 

In  a  study  of  the  heads  of  hundreds  of  cadavers  the  author  frequently 
encountered  very  large  frontal  sinuses,  but  such  extensive  pneumatization 
of  the  frontal  and  related  bones  by  the  frontal  sinuses  as  found  in  these 
two  cadavers  (Figs.  113  and  115)  is  unique  in  his  experience  and  in  all 
probability  in  the  literature  on  the  subject. 

Supernumerary  Frontal  Sinuses. — Unilateral  and  bilateral  supernu- 
merary frontal  sinuses  are  extremely  common.  They  occur  in  both  the 


PIG.  115. — An  adult  skull  showing  extensive  pneumatization  by  the  frontal  sinuses  of  the  vertical 
portion  of  the  frontal  bone.  In  Pig.  114  is  illustrated  the  supraorbital  extent  of  the  frontal  sinuses 
in  the  same  skull  (see  text,  page  147).  (After  J.  P.  S.,  Annals  of  Surgery,  December,  1916.) 

vertical  and  horizontal  portions  of  the  frontal  bone.  Multiple  frontal 
sinuses  are  placed  either  side  by  side  in  the  coronal  plane  or  one  dorsal  to 
the  other  in  the  sagittal  plane.  Intermediate  relations  are  encountered. 
The  writer  has  observed  as  many  as  six  frontal  sinuses  in  one  skull,  four 
on  one  side  and  two  on  the  other.  Cryer  observed  as  many  as  five  in  one 
skull.  Regardless  of  the  number,  each  sinus  is  normally  independent  of 
another  and  has  its  own  ostium  of  communication  with  the  frontal  region 
of  the  middle  nasal  meatus. 


SUPERNUMERARY  FRONTAL  SINUSES  151 

Cryer1  in  commenting  on  a  specimen  with  four  frontal  sinuses  placed 
side  by  side  in  the  coronal  plane  aptly  says:  "  Some  writers  would  class  the 
two  middle  sinuses  as  anterior  ethmoidal  cells  which  had  invaded  the 
frontal  bone.  If  these  cells  should  exist  without  the  two  large  sinuses, 
they  would  then  be  called  frontal  sinuses  by  these  same  writers."  In  a 
certain  sense  the  frontal  sinuses  are  always  anterior  ethmoidal  cells  which 
have  invaded  the  frontal  bone.  However,  one  cannot  get  away  from  the 
topography  of  these  supernumerary  sinuses  and  their  classification  as 
frontal  rather  than  ethmoidal  paranasal  chambers  is  eminently  proper. 
Genetically,  there  is  abundant  reason  for  multiple  frontal  sinuses  (see 
page  140). 


Sinus  froiifalisfderkr)  Sinvs  frvnfalcsfsirdstcrj 


FIG.   1 1 6. — The  frontal  sinuses  of  an  adult.      Xote  the  marked  asymmetry. 

In  Figs.  125  and  126  are  represented  dissections  of  adult  naso- 
frontal  regions  in  which  two  frontal  pits  (early  anterior  ethmoidal  cells) 
developed  sufficiently  far  to  be  topographically  frontal  sinuses.  In  Fig. 
126  the  first  and  second  frontal  pits  developed  into  frontal  sinuses;  in 
Fig.  125,  the  second  and  third.  In  both  instances  the  sinuses  communi- 
cate independently  with  the  recessus  frontalis  of  the  middle  nasal  meatus. 
At  times  when  the  frontal  sinus  exists  in  duplicate  (or  triplicate)  one 
sinus  may  encroach  bullous-like  on  the  other.  The  name  bulla  frontalis 
is,  however,  applied  to  infundibular  and  other  cells  which  encroach  upon 
the  dorsocaudal  boundary  of  the  frontal  sinus  (Figs.  117  and  118). 

A  common  type  of  duplicate  frontal  sinus  is  illustrated  on  the  left 


152  THE  FRONTAL  SINUS 

side  of  the  skull  shown  in  Fig.  120.  In  this  skull  the  single  right  sinus 
has  pneumatized  both  the  horizontal  and  vertical  portions  of  the  frontal 
bone.  On  the  left  side  the  frontal  sinus  is  present  in  duplicate.  The 
left  ventral  sinus  has  invaded  both  the  horizontal  and  vertical  portions  of 
the  frontal  bone  and  immediately  dorsal  to  it  is  another,  absolutely 
independent  frontal  sinus  which  has  pneumatized  the  remainder  of  the 
horizontal  part  of  the  frontal  bone  as  well  as  portions  of  the  greater  and 
lesser  wings  of  the  sphenoid  bone.  This  type  of  sinus  is  often  overlooked 
in  operative  procedures,  owing  to  its  depth  from  the  frontal  region,  its 
position  and  relations.  In  order  to  expose  it  from  the  frontal  region,  the 
removal  of  two  plates  of  bone  would  be  necessary. 

The  Frontal  Bulla  (bulla  frontalis). — Not  infrequently  one  or  other 
of  the  anterior  ethmoidal  cells  encroaches  upon  the  floor  of  the  frontal 

S.  fronted*  S.fronfatis 


Ccetkmoidales  &ut,fa  fivntodis 

FIG.   117. — The  frontal  sinuses  and  encroaching  ethmoidal  cells  of  an  adult  skull. 

sinus,  pushing  the  latter  balloon-like  into  the  lumen  of  the  sinus.  To 
these  frontal  extensions  of  ethmoidal  cells  is  applied  the  term  frontal 
bullae.  There  is  no  constancy,  however,  as  to  which  of  the  ethmoidal  cells 
impinges  or  encroaches  upon  the  confines  of  the  frontal  sinus  in  the  for- 
mation of  a  so-called  frontal  bulla.  It  may  be  an  extensively  developed 
cell  of  the  bulla  ethmoidalis  (bullar  cell),  of  the  infundibulum  ethmoidale 
(infundibular  cell),  or  of  the  recessus  frontalis  (frontal  cell).  The  frontal 
bulla  is,  therefore,  merely  an  extension  of  an  ethmoidal  cell  at  the  expense 
of  the  lumen  of  the  frontal  sinus  with,  however,  no  connection  whatever 


FRONTAL  BULLA 


153 


with  the  sinus.  At  times  anterior  ethmoidal  cells  arrange  themselves 
tier-like  in  the  floor  of  the  frontal  sinus  (Fig.  1 18).  Not  infrequently  they 
encroach  markedly  upon  the  nasofrontal  duct  and  cause  it  to  assume  a 
sinuous  course.  The  frontal  bulla  may  be  so  prominent  (essentially  a 
frontal  sinus)  and  so  located  that  in  the  usual  Killian  operation  upon  the 
frontal  sinus  it  would  be  the  frontal  bulla  and  not  the  frontal  sinus  that 
would  be  opened  (Fig.  118). 


FIG.   1 1 8. — A  dissection  showing  anterior  ethmoidal  cells  arranged  tier-like  in  the  floor  of  the  right 

frontal  sinus. 
Sf  =  sinus  frontalis;  Bf  =  bulla  frontalis;  Ce   =  cellula  ethmoidalis. 

The  belief  that  the  balloon-like  structure  in  the  floor  of  the  frontal 
sinus  is  always  an  ethmoidal  cell  accompanied  by  a  frontal  sinus  of  the 
same  side  is  not  based  upon  facts.  Witness,  for  example,  Fig.  85, 
in  which  is  represented  a  dissection  of  the  frontal  sinuses  showing  marked 
asymmetry.  It  will  be  noted  that  the  right  frontal  sinus  in  both  in- 
stances projects 'to  a  marked  degree  to  the  left  of  the  mid-sagittal  plane. 
The  only  evidence  of  a  right  frontal  sinus  is  the  elongated  balloon-like 
swelling  in  the  floor  of  the  left  extension  of  the  right  frontal  sinus.  Obvi- 


154 


THE  FRONTAL  SINUS 


ously  had  the  left  side  alone  been  dissected  the  natural  inference  would 
have  been  that  the  swelling  over  the  orbit  was  a  bulla  frontalis  and  that 
the  frontal  sinus  over  it  was  an  asymmetrical  left  frontal  sinus.  Strangely, 
however,  the  "bulla  frontalis"  happens  to  be  the  left  frontal  sinus  and 
the  right  frontal  sinus  occupies  the  greater  portion  of  the  fields  usually 
occupied  by  the  conjoint  right  and  left  sinuses.  Such  specimens  are  of 
not  infrequent  occurrence  and  argue  against  the  statement  that  frontal 
bullae  are  always  cranial  extensions  of  anterior  ethmoidal  cells  into  the 
lumen  of  the  frontal  sinus  of  the  same  side. 

Frontal  Sinus  Diverticula. — Rarely  frontal  sinuses  depart  markedly 
from  the  average  and  early  give  off  buds  which  develop  into  diverticula1 


FIG.  119. — A  dissection  of  the  frontal  sinuses  of  an  adult.  On  the  right  side  is  a  goodly  sized 
frontal  sinus,  in  a  sense  a  diverticulum,  immediately  dorsal  to  the  usual  frontal  sinus.  Yale  Uni- 
versity Anatomical  Series.  (See  text,  page  154.) 

that  communicate  with  the  parent  sinus  in  the  adult.  The  dissection  of 
a  male  head  shown  in  Fig.  119  is  apropos.  The  ventral  view  of  the  right 
sinus  is  more  or  less  typical.  The  sinus  projects  beyond  the  mid-sagittal 
plane  to  the  left,  a  very  common  variation.  Its  greatest  transverse 
measurement  is  50  mm.  and  the  greatest  ventrodorsal  measurement  is 
but  10  mm.  It  does  not  extend  to  any  appreciable  degree  over  the 
orbit,  but  projects  far  into  the  squama  frontalis.  In  these  respects  it 
contrasts  strongly  with  the  left  frontal  sinus. 

On  the  dorsal  wall  of  the  right  frontal  sinus,  as  shown  in  the  ventral 

1  J.  Parsons  Schaeffer,  Annals  of  Surgery,  Sept.,  1912. 


DIVERTICULA  155 

view  in  the  larger  figure,  immediately  lateral  to  the  line  X-Y,  at  point  B, 
is  noted  a  round  ostium,  about  2  mm.  in  diameter.  This  ostium  led  to 
the  finding  of  the  large  diverticulum  immediately  dorsal  to  the  usual  and 
normal  sinus.  Careful  dissection  demonstrated  the  diverticulum  as 
communicating  with  the  right  frontal  sinus  proper  only,  through  the  small 
aperture  B,  shown  in  both  figures.  In  the  small  figure  to  the  left,  a 
sagittal  section  through  the  right  frontal  sinus  is  revealed,  the  large  diver- 
ticulum from  the  sinus  proper,  dorsal  in  position.  A  reference  to  the 
figure  will  show  the  outline  of  the  diverticulum,  passing  well  over  the 
orbit,  beneath  and  dorsal  to  the  right  frontal  sinus  proper.  It  will  be 
noticed  that  three  plates  of  bone  intervene  between  the  soft  tissues  of 
the  forehead  and  the  dura  mater:  first,  the  plate  (i)  ventral  to  the  right 
frontal  sinus  proper;  second,  the  plate  (2)  dorsal  to  the  sinus  proper  and 
ventral  to  the  diverticulum;  third,  the  plate  (3)  dorsal  to  the  diverticulum 
and  forming  the  ventral  boundary  of  the  anterior  cranial  fossa  (F  in  the 
figure  designates  the  anterior  cranial  fossa). 

The  diverticulum  measures  37  mm.  in  its  greatest  transverse  dimen- 
sion and  30  mm.  in  its  greatest  ventrodorsal  extent.  It  projects  somewhat 
into  the  squama  frontalis,  and  extends  well  dorsad  into  the  pars  orbitalis 
of  the  frontal  bone. 

The  frontal  sinus  proper  of  the  right  side  communicates  with  the 
frontal  recess  of  the  middle  nasal  meatus  indicated  by  the  black  arrow 
(the  middle  nasal  concha,  C,  is  partly  cut  away  so  as  to  expose  the  fron- 
tal recess) .  The  ethmoidal  inf undibulum  (£)  ends  blindly  in  an  anterior 
ethmoidal  cell.  The  large  diverticulum  communicates  with  the  right 
frontal  sinus  proper  through  the  ostium  marked  B  as  indicated  by  the 
white  arrows  in  both  figures. 

Had  the  right  frontal  sinus  proper,  as  shown  in  the  large  figure,  been 
opened  surgically  in  the  living  subject,  the  large  diverticulum,  dorsal  in 
position,  would  in  all  likelihood  have  been  entirely  overlooked.  The 
natural  inference,  of  course,  would  have  been  that  the  bony  plate  marked 
"2"  was  the  plate  separating  the  frontal  sinus  from  the  dura  mater  and 
brain.  A  reference  to  the  sketch  in  the  sagittal  plane  demonstrates  the 
fallacy  of  such  a  conclusion. 

In  concluding  this  note  a  word  as  to  the  probable  genesis  of  this  large 
diverticulum  may  not  be  amiss.  There  is  all  evidence  in  the  specimen 
that  the  right  frontal  sinus  proper  had  its  genesis  in  an  anterior  ethmoidal 
cell,  which  in  turn  had  its  genesis  in  one  of  the  frontal  furrows  on  the 
lateral  wall  of  the  frontal  recess  of  the  fetus.  The  ethmoidal  cell  continued 
its  development  sufficiently  far  to  become  topographically  the  right  frontal 


156  THE  FRONTAL  SINUS 

sinus.  The  natural  inference  is,  since  all  of  the  paranasal  chambers  are 
primarily  outgrowths  from  preformed  nasal  spaces,  that  sometime  during 
the  development  of  the  right  frontal  sinus  a  dorsal  evagination  from  the 
frontal  sinus  grew  into  the  plate  of  bone  which  separated  the  right  frontal 
sinus  from  the  dura  mater.  The  evaginated  sac  continued  to  grow  and  the 
bone  immediately  surrounding  the  sac  was  resorbed;  the  two  processes, 


Sinus  frcnJaJis 


FIG.  120. — A  specimen  in  which  there  is  a  duplication  of  the  frontal  sinus  on  the  left  side.  The 
anterior  of  the  two  sinuses  is  largely  confined  to  the  vertical  portion  of  the  frontal  bone  and  the  poste- 
rior to  the  horizontal  portion.  In  the  usual  Killian  operation  on  the  frontal  sinus  the  posterior  of  the 
two  left  sinuses  would  in  all  likelihood  be  overlooked.  The  posterior  sinus  might  be  diseased  and 
the  anterior  one  opened  with  negative  findings.  (After  J.  P.  S.) 

growth  of  the  sac  and  resorption  of  bone,  taking  place  para  passu  with  the 
further  growth  of  the  sinus  proper.  In  this  manner  the  large  diverticulum 
or  accessory  frontal  sinus  was  formed  dorsal  to  the  frontal  sinus  proper. 
The  plate  of  bone  marked  B,  although  very  thin,  not  being  entirely 
resorbed,  remained  as  a  partition,  completely  separating  the  two  cavities, 
save  at  the  point  of  the  original  budding  of  the  diverticulum;  the  point  of 


A(, KXKSIS  OF    I  kOXTAI.   SIXLs 


157 


origin  of  the  sac  remaining,  of  course,  as  the  ostium  of  communication 
between  the  two  cavities  in  the  adult. 

Agenesis  of  the  Frontal  Sinus. — Unilateral  and  bilateral  absence 
of  the  frontal  sinus  has  been  reported.  Boege  claims  to  have  found 
bilateral  absence  in  4  per  cent,  of  203  skulls  examined.  The  writer 
questions  the  frequency  of  agenesis  in  Boege's  results,  because  in  a  large 
series  of  specimens  (well  over  300)  the  nearest  approach  to  an  absent 


FIG.  121. — An  adult  skull  in  which  it  was  believed  that  the  frontal  sinuses  were  wholly  wanting. 
A  large  frontal  wedge  of  bone  exposed  the  cerebral  hemispheres,  yet  failed  to  expose  frontal  sinuses. 
Further  dissection  showed  the  frontal  sinuses  present  in  duplicate  on  both  the  right  and  left  sides  in 
the  horizontal  portion  of  the  frontal  bone,  hugging  the  ethmoidal  labyrinth  and  extending  well  over 
the  orbit.  The  frontal  sinuses  are  indicated  by  cross-hatching  and  by  dotted  lines. 

frontal  sinus  is  shown  in  Figs.  129  and  123.  In  Fig.  129  a  cavity  in 
communication  with  the  frontal  recess  extends  above  the  nasion  which  in 
reality  is  a  frontal  sinus.  However,  it  is  totally  absent  in  the  vertical 
portion  of  the  frontal  bone  and  doubtless  would  be  considered  a  case  of 
absent  frontal  sinus  by  many  investigators.  In  the  specimen  represented 
in  Fig.  1 23  both  frontal  sinuses  are  seemingly  wholly  wanting.  How- 
ever, this  is  true  only  of  the  vertical  portion  of  the  frontal  bone.  The 


158 


THE  FRONTAL  SINUS 


small  openings  expose  goodly  sized  frontal  sinuses  in  the  horizontal  or 
orbital  portion  of  the  bone,  hugging  closely  the  ethmoid  labyrinth  through- 
out and  extending  medially  along  the  orbit.  Frontal  sinuses  in  this  posi- 
tion would  be  wholly  missed  by  the  usual  frontal  approach  surgically  and 
in  all  likelihood  would  be  classed  as  wanting.  Frequently  sinuses  in  this 
position  are,  of  course,  ethmofrontal  rather  than  purely  frontal.  How- 
ever, in  this  particular  instance  the  sinuses  are  wholly  within  the  confines 
of  the  frontal  bone. 

Meyer  reports  bilateral  absence  of  the  frontal  sinus  in  a  white  male, 
aged  52  years.  His  case  likewise  showed  a  frontal  recess  which  enlarged  in 
a  slightly  dilated  extremity  about  3  mm.  superior  to  the  nasofrontal  suture. 


Sin  us  fronts  -£**$••- 


'ijSjnusfrontalis 


FIG.    122. — An  adult  skull  with  extremely  small  frontal  sinuses. 

Errors  have  doubtless  been  made  in  assuming  the  frontal  sinus  absent 
in  those  cases  in  which  there  was  no  pneumatization  of  the  frontal  or 
vertical  portion  of  the  frontal  bone  (squama  f rontalis) .  It  is  well  to  recall 
that  the  frontal  sinus  is  genetically  an  outgrowth  from  the  middle  nasal 
meatus  and  that  the  first  evidence  of  the  sinus  must  not  be  sought  in  the 
vertical  portion  of  the  frontal  bone.  Indeed,  in  some  instances  the  frontal 
sinus  never  does  invade  the  vertical  portion  of  the  frontal  bone,  develop- 
ment taking  place  wholly  in  the  horizontal  or  orbital  portion. 

Witness,  for  example,  the  skull  represented  in  Fig.  121.  This 
specimen  was  exhibited  as  a  skull  with  absent  frontal  sinuses.  The  verti- 
cal saw-cut  exposed  both  frontal  lobes  of  the  brain  and  met  at  right  angles 


AGENESIS  OF  FRONTAL  SINUS 


159 


a  deep  horizontal  cut  made  at  the  level  of  the  nasion  (point  of  contact  of 
the  frontal  bone  with  both  nasals).  Even  with  this  large  wedge  of  bone 
removed,  no  frontal  sinus  was  exposed,  and  in  a  sense  the  exhibitor  of  the 
skull  was  justified  in  declaring  the  frontal  sinuses  absent.  Through  the 
kindness  of  Doctor  Hoffman  the  writer  was  given  an  opportunity  to 
examine  the  skull.  The  orbital  type  of  frontal  sinus  was  at  once  suspected. 
Small  trephine  openings  made  at  the  highest  point  of  the  nasal  processes 
of  the  maxillae  revealed  two  fairly  large  frontal  sinuses  hugging  closely  the 


Os  nccsale 


FIG.  123. — An  adult  skull  with  a  persistent  frontal  or  metopic  suture.  Note  that  the  frontal 
sinuses  are  completely  wanting  in  the  vertical  or  frontal  portion  of  the  frontal  bone,  but  present  in 
the  horizontal  or  orbital  portion.  The  vertical  saw  cut  in  the  frontal  plane  failed  to  reveal  frontal 
sinuses,  and  it  was  believed  that  there  was  total  agenesis  of  these  paranasal  chambers.  Further 
search,  however,  resulted  in  finding  frontal  sinuses  as  depicted  in  the  illustration. 

ethmoidal  labyrinth  and  extending  for  some  distance  into  the  horizontal 
portion  of  the  frontal  bone  over  the  medial  and  cephalic  wall  of  the  orbit. 
On  the  left  side  a  supernumerary  sinus  was  found  immediately  dorsal  to 
the  one  ventrally  placed.  Moreover,  a  supernumerary  frontal  sinus  was 
found  on  the  right  side  medial  to  the  frontal  sinus  first  exposed  and  lateral 
in  position.  In  the  drawing  the  outlines  of  the  four  frontal  sinuses  are 
given.  They  are  wholly  dorsal  to  the  vertical  saw-cut.  The  ordinary 
procedure  for  exposing  the  frontal  sinuses  would,  of  course,  have  failed 


i6o 


THK   FRONTAL  SIM'S 


to  reveal  the  chambers  in  this  case.  Four  frontal  sinuses,  therefore, 
existed  where  a  total  absence  was  thought  to  be  the  condition. 

Very  careful  examination  is  necessary  before  one  is  justified  in  de- 
claring a  total  agenesis  of  the  frontal  sinus.1  It  is  very  rare.  Of  course, 
some  would  call  such  sinuses  ethmof rental.  At  times  the  frontal  sinus 
remains  extremely  diminutive  in  size.  It  is  very  common  to  err  in  these 
cases  and  declare  the  frontal  sinuses  absent.  Only  careful  search  and 
a  realization  of  the  great  variations  in  the  anatomy  keep  one  from  "going 
wrong." 

The  Nasofrontal  Connections  in  the  Adult. — As  stated  in  the  intro- 
duction, in  order  to  properly  interpret  points  in  the  adult  anatomy  of  a 


Sinus  frontcdis  _____ 
nasofrantalis. 


Celhlae  etJ?.  ant. 
Buttadfc 


Concha,  rtas.  rned. 
" 

Infizndib.  etk.. 


Ostiv.m  max.  aux,, 


FIG.  124. — Dissection  of  an  adult  lateral  nasal  wall  with  especial  reference  to  the  frontal  recess 
and  the  nasofrontal  connections.  Note  that  the  nasofrontal  duct  and  the  infundibulum  ethmoidale 
are  discontinuous  channels.  (See  text,  pages  161-164.) 

region,  it  is  frequently  necessary  to  revert  to  the  embryology  of  the  part 
or  parts  concerned.  This,  indeed,  is  true  of  the  nasofrontal  region.2 
Doubtless  many  of  the  erroneous  statements  extant  in  the  literature 
on  the  connections  of  the  frontal  sinus  with  the  nasal  fossa  are  the  result 

1  J.  Parsons  Schaeffer:  Further  Observations  on  the  Anatomy  of  the  Sinus  Frontalis  in  Man, 
Annals  of  Surgery,  December,  1916. 

2  J.  Parsons  Schaeffer:  The  Genesis,  Development,  and  Adult  Anatomy  of  the  Nasofrontal  Region 
in  Man,  Amer.  Jour.  Anatomy,  Vol.  20,  July,  1916. 


NASOFRONTAL  CONNECTIONS 


161 


of  drawing  conclusions  from  a  study  of  too  few  specimens,  of  studying 
adult  material  alone,  and  of  errors  in  interpretation  due  to  the  fact  that 
embryologic  and  adult  studies  were  not  carried  on  simultaneously. 

The  adult  nasofrontal  region  presents  a  varied  anatomy — a  fact  in 
accord  with  the  varied  genesis  of  the  parts  involved.  In  the  adult,  one 
usually  finds  evidence  of  the  previous  embryologic  condition  that  must 
have  obtained  in  the  particular  case.  Careful  analysis  of  the  nasofrontal 
region  reveals,  as  a  rule,  the  derivatives  of  the  frontal  furrows  or  pits  and 


CMvJa  etk,ant.(FrontvJ,  topography). 


__  Sinus  fronfailis 


_  _  _  ffecessus  frynta.lis 


O^x 

mj^fmcfat-  TMs.Tncd 

m\\\\ 


Procvxcinatus 


PIG.  125. — A  dissection  of  the  lateral  nasal  wall  showing  the  ethmoidal  cells  open  and  one  of  the 
posterior  ethmoidal  cells  projecting  into  the  body  of  the  sphenoid  bone  at  the  expense  of  the  sphenoi- 
dal  sinus.  It  will  be  noted  that  the  latter  is  extremely  small.  The  frontal  recess  receives  the  frontal 
sinus  and  certain  anterior  ethmoidal  cells.  The  uncinate  process  is  curved  caudally  and  laterally, 
thereby  exposing  the  maxillary  ostium  in  the  depth  of  the  ethmoidal  infundibulum.  It  is  in  such 
cases  that  probing  of  the  maxillary  ostium  is  possible. 

of  the  frontal  folds  or  conchae;  provided,  of  course,  these  structures  were 
differentiated.  As  stated  elsewhere,  there  are  instances  in  which  the 
lateral  wall  of  the  recessus  frontalis  does  not  become  configured  by  pits 
and  folds.  Moreover,  in  some  specimens  the  adult  anatomy  is  so  altered 
that  interpretation  is  very  difficult,  even  impossible. 

It  may  be  well  here  to  refer  to  specific  dissections  of  the  region  for 
study  and  analysis.     In  Fig.  124,  for  example,  is  represented  an  adult 


162 


THE  FRONTAL  SINUS 


nasofrontal  region  exposed  for  study  by  the  removal  of  the  operculating 
middle  nasal  concha.  There  is  positive  evidence  of  four  embryological 
frontal  furrows  or  pits.  The  first  or  most  ventral  of  the  latter  differ- 
entiated into  an  anterior  ethmoidal  cell  of  small  dimension,  communicating 
directly  with  the  middle  nasal  meatus  medial  to  the  processus  uncinatus. 
The  third  and  fourth  frontal  furrows  or  pits  likewise  developed  into 
anterior  ethmoidal  cells,  both  of  which  communicate  with  the  middle 
nasal  "meatus  cephalic  to  the  semilunar  hiatus  of  the  infundibulum  eth- 


Sinas* frontalis 

Probe  m  duttus  7tasofivufafas 

Sinits  fronfaZis 

Infa.rutib.  etk . 

Proc.unci7za.tus  . 


„ '  xx  x        Hypophysis  cereljri 
'is 
Concha.  itas.Tn&d. 


tubae 


FIG.    126. — A  dissection  in  which  the  infundibulum  ethmoidale  and  the  nasofrontal  ducts  are  not 
only  discontinuous  channels,  but  channels  in  non-alignment.     (Compare  with  Pigs.  124  and  127.) 

moidale.  The  second  frontal  furrow  or  pit  after  first  developing  into  an 
anterior  ethmoidal  cell  continued  to  extend  its  boundaries  until  it  became 
topographically  the  frontal  sinus.  It  should  be  noted  that  the  duct  of 
the  frontal  sinus  (ductus  nasofrontalis)  is  in  the  position  of  the  embryonic 
second  frontal  furrow  or  pit  and  that  it  is  in  the  same  axis  as  the  infundi- 
bulum ethmoidale  and  the  hiatus  semilunaris,  but  not  in  direct  continuity 
with  them.  The  sinus  frontalis  in  this  instance  (Fig.  124)  communicates, 
therefore,  with  the  recessus  frontalis  directly  via  the  ductus  nasofrontalis. 


NASOFRONTAL  CONNECTIONS 


Moreover,  the  infundibulum  ethmoidale  ends  blindly  as  an  anterior  eth- 
moidal  cell  (infundibular  cell)  lateral  to  the  recessus  frontalis  and  the 
ductus  nasofrontalis. 

The  anatomy  represented  in  Fig.  124  is  that  found  in  a  large 
number  of  adult  specimens  and  is  illustrative  of  one  of  the  anatomic 
types  of  this  region.  It  should  be  noted  that  the  infundibulum  ethmoidale 
is  not  directly  continuous  with  the  nasofrontal  duct,  but  that  it  bears  an 
intimate  and  important  relation  to  it.  The  relation  is,  in  a  sense,  a  con- 


sinus 


Cdlula,  eth.ant  {md.) 
Cellulae  etit.post 


ProT)e  in  dnchis 
nasofrontalis 


Cellulae  eth.omt. 


'oJtcka  jtas.supremal 
_____  Concha  nas.sup. 


^1 1  °S\  .Concha,  nasinf. 


FIG.  127. — A  dissection  of  an  adult  lateral  nasal  wall.  Especially  note  that  the  infundibulum 
ethmoidale  is  in  direct  continuity  with  the  frontal  sinus — a  bridge  of  mucous  membrane  (O)  extend- 
ing across  the  frontal  end  of  the  infundibulum  ethmoidale;  moreover,  that  the  uncinate  process  at 
its  dorsal  termination  causes  the  infundibulum  ethmoidale  to  end  in  a  deep  pocket  (X),  just  over  [the 
ostium  of  the  maxillary  sinus.  The  anatomy  of  this  specimen  is  such  that  the  maxillary  sinus  would 
perforce  become  a  cess-pool  for  an  infected  frontal  sinus.  (Compare  with  Fig.  124.) 

tiguous  but  not  a  continuous  one.  Drainage  from  the  frontal  sinus  would 
find  its  way  partly  into  the  middle  nasal  meatus  directly  and  partly  into 
the  infundibulum  ethmoidale.  An  exploratory  probe  passed  toward 
the  frontal  region  via  the  infundibulum  ethmoidale  would,  of  course,  find 
its  way  into  the  ventral,  blind  end  of  the  latter  and  not  into  the  frontal 
sinus.  To  probe  the  frontal  sinus  in  this  case  it  would  be  necessary  to  pass 
through  the  proximal  ostium  of  the  ductus  nasofrontalis  located  in  the 
recessus  frontalis. 


1 64  THE  FRONTAL  SINUS 

It  is  very  interesting  and  instructive  to  compare  the  embryologic 
anatomy  of  the  recessus  frontalis  illustrated  in  Fig.  no  with  the  adult 
anatomy  illustrated  in  Fig.  124.  In  the  former  the  third  frontal  furrow 
and  the  infundibulum  ethmoidale  are  in  the  same  axis;  in  the  latter,  the 
second  frontal  furrow  (now  the  nasofrontal  duct)  is  in  the  same  axis  as 
the  infundibulum  ethmoidale.  If  in  Fig.  36  the  sinus  frontalis  had 
developed  from  the  same  frontal  furrow  as  in  Fig  124,  the  relation  be- 
tween the  ductus  nasofrontalis  and  the  infundibulum  ethmoidale  would 
have  been  less  intimate. 

The  dissection  of  the  adult  nasofrontal  region  illustrated  in  Fig.  125 
gives  evidence  of  the  early  embryologic  frontal  furrows  or  pits.  The 
adult  derivatives  of  the  latter  are  readily  identified.  The  first  frontal 
pit  developed  into  a  small  anterior  ethmoidal  cell  which  is  in  direct  com- 
munication with  the  recessus  frontalis  by  means  of  its  ostium.  The 
second  and  the  third  frontal  pits  developed  into  the  frontal  sinuses  (sinus 
frontalis  in  duplicate).  Both  of  the  latter  communicate  directly  by  means 
of  independent  ostia  with  the  recessus  frontalis,  no  ductus  nasofrontales 
being  present.  A  study  of  the  dissection  shown  in  Fig.  125  clearly  points 
out  that  the  infundibulum  ethmoidale  terminates  blindly  (indicated  by 
a  probe)  as  an  anterior  ethmoidal  cell  (infundibular  cell)  lateral  to  the 
recessus  frontalis.  Loose  interpretation  of  the  anatomy  of  the  frontal 
region  in  this  instance  might  lead  to  the  erroneous  statement  that  the 
frontal  sinus  developed  as  an  extension  of  the  infundibulum  ethmoidale. 
One  sees  even  a  channel-like  depression  on  the  lateral  wall  of  the  recessus 
frontalis  connecting  in  a  sense  the  frontal  sinus  with  the  infundibulum 
ethmoidale.  It  is  obvious  that  the  drainage  from  the  frontal  sinus  would 
in  part  find  its  way  into  the  infundibulum  ethmoidale,  thence  via  the 
latter  to  the  ostium  maxillare  and  into  the  maxillary  sinus  (antrum  of 
Highmore) . 

In  Fig.  128  we  have  evidence  of  four  embryologic  frontal  pits.  The 
derivatives  of  these  pits  are  two  anterior  ethmoidal  cells  and  two  frontal 
sinuses,  all  in  communication  with  the  recessus  frontalis  of  the  middle 
nasal  meatus.  The  first  (most  ventral)  and  fourth  (most  dorsal)  frontal 
pits  developed  into  two  small  ethmoidal  cells.  The  second  frontal  pit 
developed  sufficiently  to  be  topographically  a  frontal  sinus  (indicated  in 
the  drawing  as  an  anterior  ethmoidal  cell) .  The  frontal  sinus  proper  took 
its  origin  from  the  anterior  ethmoidal  cell  which  had  its  genetic  point  in 
the  third  frontal  pit.  The  result  of  the  encroachment  of  the  cell  from  the 
second  frontal  pit,  is  a  narrow,  tortuous  nasofrontal  duct  communicating 
between  the  frontal  sinus  and  the  frontal  recess.  As  in  Figs.  124  and  125, 


XASOFROXTAL  CONNECTIONS 


in  Fig.  128  the  infundibulum  ethmoidale  ends  blindly  lateral  to  the  recessus 
frontalis. 

Elsewhere  mention  is  made  of  occasional  adult  specimens  in  which 
the  ductus  nasofrontalis  and  the  infundibulum  ethmoidale  are  continuous 
channels.  In  Fig.  127  is  represented  a  dissection  of  an  adult  nasof rental 
region  in  which  the  ventral  extremity  of  the  infundibulum  ethmoidale  is 
directly  continuous  with  the  ductus  nasofrontalis  and  secondarily  with 
the  sinus  frontalis.  Moreover,  the  dissection  shows  a  plate  of  tissue 
intervening  between  the  free  border  of  the  processus  uncinatus  and  the 
bulla  ethmoidalis,  thus  bridging  over  the  ventral  extremity  of  the  infundi- 


Cellnlae  etk.  ant. 
Cettulae  etk.post. 
Sinus 


Hypophysis  cerebri , 


ConcJia  ?tas.  sup. 
Concha,  nas.  ?ned 


_  Sinus  fronfatis 
in  ductus  nasofrontctlis 


Concha  nas.  wed. 


Ostium  inaxillare 


PIG.  128. — Dissection  of  an  adult  lateral  nasal  wall.  Especially  note  the  tortuous  and  narrow 
nasof rental  duct  and  its  discontinuity  with  the  ethmoidal  infundibulum.  Moreover,  note  the  im- 
pingement of  one  of  the  anterior  ethmoidal  cells  on  the  confines  of  the  nasofrontal  duct.  Such 
nasofrontal  connections  are  inefficient  as  drainage  channels,  and  readily  occluded  by  inflammatory 
conditions. 

bulum  ethmoidale  and,  in  a  sense,  replacing  the  hiatus  semilunaris  in  this 
position.  One  encounters  difficulty  in  interpreting  the  anatomy  of  the 
nasofrontal  connections  in  this  specimen.  Did  the  frontal  sinus  develop 
from  the  ethmoidal  infundibulum  (by  a  direct  extension  or  from  an  in- 
fundibular cell)  or  from  a  second  frontal  pit  (early  anterior  ethmoidal  cell)  ? 
The  infundibulum  by  its  ventral  and  cephalic  extension  usually 
comes  into  topographic  relationship  with  some  of  the  anterior  ethmoidal 
cells  which  arise  from  the  frontal  pits.  In  this  instance  (Fig.  127)  a 


1 66  THE  FRONTAL  SINUS 

relationship  may  early  have  been  established  with  the  second  frontal  pit. 
Resorption  of  the  intervening  barrier  would,  of  course, bring  the  ethmoidal 
infundibulum  and  its  semilunar  hiatus  into  direct  continuity  with  the 
anterior  ethmoidal  cell  arising  from  the  second  frontal  pit,  likewise  with 
the  frontal  sinus.  Moreover,  the  specimen  gives  positive  evidence  of 
three  frontal  pits  (now  cellulae  ethmoidales  anterior).  Whether  an  addi- 
tional frontal  pit,  which  gave  rise  to  the  frontal  sinus,  was  present  in  the 
position  of  the  adult  nasofrontal  duct  is,  of  course,  impossible  to  say.  Two 
of  the  anterior  ethmoidal  cells  are  separated  by  a  considerable  interval. 
This  space  may  have  been  the  second  frontal  pit.  Again,  the  two  frontal 
pits  in  question  (cellulae  ethmoidales  anterior)  may  have  been  crowded 
apart  by  a  bullous-like  ventral  and  cephalic  growth  of  the  ethmoidal  in- 
fundibulum in  the  establishment  of  the  frontal  sinus. 

Drainage  from  the  frontal  sinus  in  such  instances  (Fig.  127)  would 
pass  almost  wholly  into  the  ethmoidal  infundibulum  and  via  the  latter 
to  the  ostium  maxillare,  thence  into  the  maxillary  sinus.  Should  the  floor 
of  the  ethmoidal  infundibulum  in  such  cases  be  largely  replaced  by  an 
elongated  ostium  maxillare  (a  rather  common  occurrence,  Fig.  103), 
the  frontal  sinus  and  the  maxillary  sinus  would  from  a  practical  mew- 
point  be  in  direct  communication.  It  should  be  recalled  that  the  maxil- 
lary sinus  is  genetically  an  outgrowth  from  the  floor  or  lateral  wall  of  the 
infundibulum  ethmoidale  and  that  the  initial  area  of  the  outgrowth  varies 
considerably  in  extent,  thus  accounting  for  the  varied  size  of  the  adult 
ostium  maxillare. 

The  Nasofrontal  Duct  (ductus  nasofrontalis,  infundibulum  of  the 
frontal  sinus). — The  duct  leading  from  the  frontal  sinus  to  the  nasal  fossa 
is  extremely  variable  in  its  anatomy.  Indeed,  a  large  number  of  frontal 
sinuses  do  not  have  true  ducts  connecting  them  with  the  frontal  recess 
of  the  middle  nasal  meatus.  In  such  cases  the  frontal  sinus  extends  well 
down  toward  the  nasal  fossa  and  communicates  directly  by  means  of  an 
ostium  with  the  frontal  recess.  In  a  general  way  it  may  be  stated  when 
the  frontal  sinus  develops  by  a  direct  extension  of  the  frontal  recess  that 
its  relations  with  the  frontal  recess  in  the  adult  will  be  more  intimate. 
On  the  other  hand,  when  the  sinus  develops  from  one  of  the  anterior 
ethmoidal  cells  it  will  more  frequently  communicate  with  the  frontal 
recess  by  means  of  a  variable  duct.  It  should,  however,  be  stated  that 
a  goodly  number  of  adult  frontal  sinuses  with  a  genesis  from  anterior 
ethmoidal  cells  do  not  have  nasofrontal  ducts.  Indeed,  there  are  more 
frontal  sinuses  encountered  in  which  true  ducts  of  communication  with 
the  frontal  recess  are  wanting  than  otherwise  (Figs.  125  and  129). 


XASOFROXTAL  DUCT 


I67 


The  nasofrontal  duct  when  present  may  be  straight  and  short,  or 
straight  and  relatively  long.  Again,  it  may  be  long  and  more  or  less 
tortuous  or  serpentine.  Witness,  for  example,  the  specimen  shown  in 
Fig.  128,  in  which  the  nasofrontal  duct  is  long,  narrow  and  curved.  It 
has  very  definitely  two  ostia  frontalia,  one  proximal  or  nasal  in  position 
and  the  other  distal  or  frontal.  The  duct  is  encroached  upon  by  an  an- 
terior ethmoidal  cell  (really  a  second  frontal  sinus)  which  developed  from 
the  second  frontal  furrow.  The  slightest  swelling  of  the  mucosa  of  such 
narrow  and  tortuous  nasofrontal  ducts  will,  of  course,  occlude  the  passage 
of  communication  between  the  sinus  and  the  nasal  fossa. 


FIG.  129. — The  lateral  nasal  wall  of  an  adult,  with  a  small  frontal  sinus  and  an  absent  naso- 
frontal duct.  Indeed,  the  sinus  is  ethmofrontal  and  the  anatomy  such  that  one  might  consider  the 
frontal  sinus  absent.  It  would  not  be  reached  by  the  usual  Killian  operation. 

In  some  instances  the  nasofrontal  duct  is  roomy  and  possesses  large 
nasal  and  frontal  ostia,  thus  affording  a  better  drainage  channel  for  the 
sinus.  The  efficiency  of  the  duct  is  usually  in  direct  ratio  to  its  length, 
diameter  and  directness  (Figs.  126  and  130). 

The  nasofrontal  duct  with  its  proximal  or  nasal  ostium,  or  in  the 
absence  of  a  true  duct  the  proximal  ostium  frontale  (in  the  latter  case 
there  is  no  distal  ostium  frontale),  bears  a  varied  relation  to  the  ventral 
extremity  of  the  infundibulum  ethmoidale.  The  latter  usually  ends 
blindly  lateral  to  the  terminal  (nasal)  portion  of  the  nasofrontal  duct. 
The  ethmoidal  infundibulum  and  the  nasofrontal  duct  are  at  times  in  the 


i68 


THE  FRONTAL  SINUS 


same  axis  (Figs.  124  and  197).  Again,  the  nasof rental  duct  with  its 
proximal  or  nasal  ostium  is  not  in  alignment  with  the  ethmoidal  infundibu- 
lum.  Witness,  for  example,  Fig.  126,  where  the  proximal  ostium  frontale 
is  located  medial  to  the  cephalic  extremity  of  the  processus  uncinatus. 
Drainage  in  the  latter  instance  would  in  a  large  measure  be  diverted 
into  the  middle  nasal  meatus  directly.  Moreover,  one  encounters  speci- 
mens in  which  shallow  gutter-like  depressions  on  the  lateral  wall  of  the 


»y.  frortta.lis 


- 

I 


FIG.   130. — The  mucous  membranes  of  the  right  frontal  and  maxillary  sinuses  exposed.      Note  the  reg- 
ular nasofrontal  duct.     The  old  term  "infundibulum  of  the  frontal  sinus  "  applies  well  in  this  case. 

frontal  recess  connect  up  the  nasofrontal  duct  with  the  ethmoidal  infundi- 
bulum. Such  depressions  must  not  be  confused  with  the  nasofrontal 
duct  (Fig.  125).  Finally,  it  is  well  to  remember  that  occasionally  the 
nasofrontal  duct  and  the  ethmoidal  infundibulum  are  continuous  channels. 
In  the  vast  majority  of  instances,  however,  the  nasofrontal  duct  and  the 
ethmoidal  infundibulum  are  discontinuous  channels,  save  for  a  slight 
depression  that  occasionally  extends  between  them. 

Concluding  Considerations. — In  most  cases  in  the  first  years  of 
childhood,  and  in  many  instances  in  the  adult,  the  frontal  sinus  owing 


CONCLUDING  CONSIDERATIONS  169 

to  its  relations  cannot  readily  be  reached  from  the  forehead.  As  pointed 
out  elsewhere,  in  many  young  children  and  not  infrequently  in  adults 
there  is  no  frontal  sinus  in  the  squama  frontalis  (frontal  or  vertical  portion 
of  the  frontal  bone)  or  at  best  but  sparsely  developed  in  its  base.  In 
such  cases  the  sinus  is  best  exposed  in  the  region  where  the  frontal  bone 
meets  both  the  nasal  bone  and  the  frontal  (nasal)  process  of  the  maxilla. 

The  clinician  must  bear  in  mind  that  there  is  no  unvarying  typical 
type  of  frontal  sinus.  Great  variations  are  encountered.  The  prominence 
of  the  superciliary  ridges  or  eminences  (arcus  superciliares)  is  very  un- 
reliable as  an  index  of  the  location  and  extent  of  the  frontal  sinuses. 
Indeed,  the  author's  studies  and  observations  would  seem  to  indicate 
that  the  ridges  should  be  entirely  ignored  in  clinical  work.  While  it  is 
true  that  the  right  and  left  sinuses  are  separated  by  a  bony  partition 
(septum  sinuum  frontalium) ,  it  is  equally  true  that  the  dividing  partition 
is  rarely  located  in  the  mid-sagittal  plane,  save  immediately  dorsal  to 
the  nasal  bones.  Indeed,  one  or  the  other  frontal  sinus  may  occupy 
the  whole  frontal  region,  the  septum  being  placed  obliquely  in  both  the 
semi-sagittal  and  semi-coronal  planes,  so  that  the  larger  sinus  occupies 
a  ventral  position;  that  is,  in  front  of  the  smaller  sinus.  This  is  important 
clinically,  for  a  healthy  sinus  may  be  opened  surgically  on  the  opposite 
side,  the  diseased  and  sought  sinus  being  dorsal  to  it.  Moreover,  it  is 
easy  to  err  in  such  cases  by  believing  that  a  supernumerary  frontal  sinus 
is  present  when  in  reality  it  is  merely  an  extension  of  the  sinus  belonging 
to  the  other  side  (Fig.  85). 

Deficiencies  or  dehiscences  in  the  osseous  walls  of  the  frontal  sinus 
are  of  occasional  occurrence.  The  defects  are  either  congenital  or  patho- 
logic in  origin;  others  are  the  result  of  extreme  pneumatization.  The 
author  finds  that  dehiscences  in  the  orbital  wall  are  the  most  frequent. 
The  cerebral  wall  and  the  frontal  or  ventral  wall  above  the  supraorbital 
border  (mar go  supraorbitalis)  have  been  found  defective  in  a  few  instances. 
But  one  specimen  was  found  in  which  the  inter-sinus  septum  was  per- 
forated, leading  to  a  connection  of  the  two  sinuses.  The  dehiscences  are 
either  covered  over  with  a  mucoperiosteum  or  with  a  mucous  membrane 
only.  When  the  defect  is  a  congenital  one  the  periosteum  apparently 
ends  at  the  margin  of  the  ostium  dehiscence.  The  possibility  of  infection 
extending  to  the  tissues  of  the  orbit  and  to  the  meninges  through  such 
osseous  defects  must  be  kept  in  mind. 

Partial  septa  of  varying  degree  frequently  project  from  the  walls  of 
the  frontal  sinus.  They  divide  the  cavity  of  the  sinus  incompletely  into 
subcompartments,  some  of  which  not  infrequently  partake  of  the  nature 


1 70  THE  FRONTAL  SINUS 

of  deep  recesses  and  in  consequence  are  drained  with  difficulty.  The 
belief  that  these  recesses  at  times  form  enclosed  cells  within  the  frontal 
sinus  is,  according  to  the  writer's  observations,  unwarranted.  It  would 
appear  that  supernumerary  frontal  sinuses  and  impinging  ethmoidal  cells 
have  at  times  been  erroneously  designated  as  "enclosed  recess  cells." 
Moreover,  the  olfactory  fissure  at  times  projects  into  the  dorsomedial 
wall  of  the  sinus  as  a  bleb-like  ridge.  Care  must  be  exercised  in  operative 
procedures  lest  the  impinging  olfactory  fissure  be  broken  into  and  the 
dura  mater  exposed  to  the  infection.  The  impingement  of  the  olfactory 
fissure  is  especially  prominent  when  the  dorsal  portion  of  the  inter-sinus 
septum  is  deviated  to  one  side. 

Agenesis  of  the  frontal  sinus  is  rare;  duplication  and  triplication 
common.  The  diseased  sinus  may  be  the  one  dorsal  in  position  and 
orbital  in  type  (Fig.  120).  The  skiagram  may  not  reveal  it.  In  some 
cases  the  frontal  sinus  is  entirely  absent  in  the  irontal  or  vertical  portion 
of  the  frontal  bone,  but  present  and  roomy  in  the  orbital  or  horizontal 
portion,  hugging  closely  the  ethmoid  labyrinth  and  extending  far  dorsad 
and  laterad  into  the  roof  of  the  orbit.  Indeed,  in  adults  where  the  frontal 
sinus  exists  in  duplicate  of  the  type  shown  in  Fig.  119  it  may  be  necessary 
to  open  the  ventral  sinus  to  get  to  the  one  dorsal  in  position.  The  skiagram 
is  of  great  value  in  determining  the  presence  and  extent  of  the  frontal 
sinus  in  the  region  of  the  forehead,  e.g.,  in  the  vertical  portion  of  the  frontal 
bone.  Where  supernumerary  frontal  sinuses  exist  and  where  the  sinuses 
are  of  the  orbital  type,  even  skiagraphy  may  furnish  erroneous  results. 
Of  course,  rhinoscopic  examination  is  an  invaluable  supplement  in  the 
diagnosis.  Electrical  transillumination  is  unreliable. 

In  this  connection  it  may  not  be  amiss  to  quote  briefly  from  Turner 
and  Porter.1  "Although  the  older  method  of  investigating  the  frontal 
sinus  by  electrical  transillumination  undoubtedly  possesses  some  value 
as  a  means  of  delineating  the  vertical  portion  of  the  cavity  in  the  frontal 
bone,  it  frequently  fails  us  when  it  is  most  desirable  that  we  should  obtain 
definite  information  as  to  whether  the  sinus  is  present  or  not.  Further, 
it  is  quite  useless  as  a  means  oi  ascertaining  the  existence  of  a  horizontal 
or  orbital  extension  of  the  cavity  or  for  the  purpose  of  defining  its  relations 
with  the  ethmoidal  cells.  If  a  frontal  sinus  exists  it  is  possible  to  demon- 
strate its  presence  by  skiagraphy,  provided  the  picture  is  a  good  one  and 
that  the  rays  have  passed  through  the  head  at  the  correct  angle.  Should 
the  skiagram  not  be  satisfactory,  a  second  or  even  a  third  one  should  be 
taken  in  order  to  settle  this  point. 

1  The  Skiagraphy  of  the  Accessory  Nasal  Sinuses,  Edinburgh,  1912. 


CONCLUDING  CONSIDERATIONS  171 

If  the  rays  have  been  incorrectly  directed  through  the  sagittal  di- 
ameter of  the  head  from  a  point  too  far  above  the  external  occipital 
protuberance  a  small  frontal  sinus  may,  in  consequence,  be  invisible  in  the 
lower  part  of  the  frontal  bone.  If,  on  the  other  hand,  the  rays  have  been 
transmitted  through  the  skull  from  a  point  some  distance  below  that  land- 
mark, the  ethmoidal  cell  may  be  projected  onto  the  frontal  sinus  area  and 
thus  deceive  us  as  to  the  true  condition.  Coakley1  has  pointed  out  that 
a  small  frontal  sinus  lying  parallel  with  the  supraorbital  margin  may  escape 
detection  upon  the  skiagram.  Apart  from  these  faulty  or  exceptional  con- 
ditions, if  a  frontal  sinus  exists  the  anteroposterior  skiagram  will  reveal  it, 
and  if  there  should  be  any  doubt  in  the  observer's  mind  a  profile  view  of  the 
head  will  prove  of  further  assistance.  From  time  to  time  the  surgeon  has 
operated  upon  the  frontal  sinus  area  and  found  that  the  cavity  was  absent; 
with  a  preliminary  use  of  the  X-rays,  this  mistake  should  no  longer  be  made." 

In  a  general  way,  as  stated  in  a  previous  paragraph,  wrhen  the  frontal 
sinus  develops  from  an  anterior  ethmoidal  cell — frontal  or  infundibular — 
the  adult  cavity  will  more  frequently  have  a  nasofrontal  duct.  The 
tortuosity  of  the  duct  will,  of  course,  depend  upon  the  location  of  the  cell 
from  which  the  sinus  frontalis  develops  and  upon  the  degree  of  develop- 
ment and  disposition  of  neighboring  ethmoidal  cells.  On  the  other  hand, 
when  the  frontal  sinus  develops  by  a  direct  extension  of  the  frontal  recess 
there  will,  in  all  likelihood,  be  no  nasofrontal  duct  and  the  sinus  proper 
be  in  direct  relationship  and  communication  with  the  adult  recessus 
frontalis  of  the  meatus  medius.  The  connection  of  the  nasofrontal  duct 
is,  of  course,  dependent  upon  the  genesis  of  the  frontal  sinus ;  usually, 
however,  the  frontal  sinus  communicates  with  the  frontal  recess  of  the 
middle  nasal  meatus. 

The  outlet  of  the  frontal  sinus  is  readily  influenced  by  variations  in 
the  anatomy  of  the  related  parts  and  by  inflammatory  conditions.  An 
asymmetrical  nasal  septum  may  encroach  upon  the  frontal  ostium  or  the 
terminal  portion  of  the  nasofrontal  duct.  The  size  and  disposition  of  the 
anterior  group  of  ethmoid  cells  likewise  have  an  important  bearing. 
Enlargement  of  the  uncinate  process  and  the  ethmoidal  bulla  frequently 
encroach  upon  the  ethmoidal  infundibulum  and  the  semilunar  hiatus  and 
secondarily  affect  the  outlet  of  the  frontal  sinus.  A  large  middle  nasal 
concha,  because  of  its  relationship,  readily  impinges  upon  the  site  of  the 
frontal  outlet.  Then,  again,  the  whole  middle  meatus  may  be  so  narrowed 
toward  the  frontal  region  that  the  space  is  insufficient  for  good  frontal 
drainage.  The  latter  may  be  the  condition  in  apparently  normal  noses. 

1  Annals  of  Otology,  Rhinology  and  Laryngology,  1905. 


172  THE  FRONTAL  SINUS 

The  well-known  clinical  fact  that  the  sinus  maxillaris  (antrum  of 
Highmore)  is  frequently  a  cess-pool  for  drainage  from  the  frontal  region 
of  the  meatus  medius,  doubtless  leads  to  the  erroneous  belief  that  the  in- 
fundibulum  ethmoidale  is,  in  the  majority  of  instances,  directly  continuous 
anatomically  with  the  nasofrontal  duct  or,  in  the  absence  of  the  latter, 
directly  with  the  sinus  frontalis.  It  should,  however,  be  pointed  out,  despite 
the  fact  that  direct  anatomical  continuity  is  uncommon,  from  a  clinical  view- 
point in  as  many  as  50  per  cent,  of  adult  cases  the  relationship  is  so  intimate 
between  the  infundibulum  ethmoidale  and  the  sinus  frontalis  or  its  duct 
(ductus  nasofrontalis)  and  certain  of  the  anterior  ethmoidal  cells  (some 
infundibular,  others  frontal}  that  drainage  from  these  paranasal  chambers 
finds  its  way  in  whole  or  in  part  into  the  infundibulum  ethmoidale,  thence 
via  the  latter  to  the  ostium  maxillare  and  through  it  into  the  sinus  maxillaris. 

If  in  those  cases  in  which  the  sinus  frontalis  (or  its  duct)  is  directly 
continuous  anatomically  with  the  ventral  extremity  of  the  infundibulum 
ethmoidale  the  ostium  maxillare  should  occupy  the  greater  portion  of  the 
floor  of  the  infundibulum  ethmoidale  (a  condition  encountered)  the  frontal 
sinus  and  certain  of  the  anterior  ethmoidal  cells  (frontal  and  infundibular) 
would,  anatomically  and  clinically,  be  in  direct  communication  with  the 
sinus  maxillaris. 

Intranasal  opening  of  the  frontal  sinus  for  the  purpose  of  drainage  in 
chronic  suppuration  is  now  deemed  feasible  and  is  attended  with  no  greater 
risk  than  is  the  extranasal  operation.  As  stated  before,  the  surgeon  must 
continually  bear  in  mind  that  the  ventral  portion  of  the  ethmoidal  laby- 
rinth is  intimately  related  with  the  sinus  frontalis  and  that  both  of  these 
paranasal  chambers  present  great  variations.  X-ray  examinations  are  of 
great  help  in  determining  the  anatomy  of  the  particular  field.  Moreover, 
certain  landmarks,  e.g.,  the  concha  nasalis  media,  the  processus  uncinatus, 
the  bulla  ethmoidalis  and  the  entrance  to  the  recessus  frontalis  are  fairly 
constant  in  their  location  and  are  of  aid  to  the  operator  in  the  intranasal 
approach  of  the  sinus  frontalis.  The  proximal  or  nasal  ostium  of  the 
frontal  sinus  is  usually  located  in  the  recessus  frontalis,  and  is  related 
ventrally  to  a  crest  on  the  sinus  surface  of  the  ectal  table  of  the  frontal 
bone;  dorsally  to  the  ethmoidal  labyrinth;  laterally  to  the  anterior  cellulse 
ethmoidales  located  between  the  ostium  and  the  lacrimal  bone ;  and  medi- 
ally to  the  nasal  process  of  the  frontal  bone.  It  is,  of  course,  obvious  that 
ethmoidal  cells  must  be  ablated  in  establishing  good  drainage  for  the  sinus 
frontalis  and  that  the  surgical  approach  is  more  direct  than  is  the  natural 
and  often  tortuous  nasofrontal  connection.  Moreover  the  latter  is  not 
infrequently  closed  by  inflammatory  states  of  the  mucous  membrane. 


V-THE  SINUS  SPHENOIDALIS 


CHAPTER  V 

THE  SINUS  SPHENOIDALIS 

THE  FETAL  STAGE 

The  sphenoidal  sinus  (sinus  sphenoidalis)  primarily  arises  in  relation 
with  the  posterior  cupola  or  dome  of  the  cartilaginous  nasal  capsule  and  is 
genetically  demonstrable  as  early  as  the  fourth  month  of  fetal  life.  The 
cupola-shaped  recess  or  terminal  nasal  sinus  (sinus  terminalis),  above 
referred  to,  is  poorly  developed  in  man;  yet  is,  strictly  speaking,  the  primi- 
tive sphenoidal  sinus.  The  wall  of  the  terminal  sinus  gives  the  foundation 
for  the  sphenoidal  turbinal  or  concha  (ossiculum  Bertini).  The  actual 
bone  arises  through  ossification  which  begins  in  the  fifth  month  of  fetal 
life  as  two  primary  and  several  secondary  centers  (see  page  43). 


Laleral^leof 
earlilui/f 


FIG.   131. — Outline  drawing  of  a  frontal  section  through  the  dorsal  portion  of  the  nasal  cavity. 
X  10.     Human  embryo,  aged  120  days. 

It  must  be  clearly  understood  that  no  portion  of  the  fetal  sphenoidal 
sinus  is  contained  within  the  sphenoid  bone.  It  is  necessary  that  resorp- 
tion  of  the  intervening  nasal  capsule  takes  place  before  the  terminal  nasal 
sinus  (early  sphenoidal  sinus)  can  come  into  actual  contact  with  the  body 
of  the  sphenoid  bone.  Indeed,  such  resorption  does  occur  subsequently. 
In  a  certain  sense,  therefore,  the  fetal  sphenoidal  sinus  is  a  constricted 
portion  of  the  nasal  fossa.  The  proximal  end  of  the  constriction  remains  as 
the  ostium  of  the  sinus  and  is  always  located  cephalic  to  the  highest  nasal 
concha  that  may  be  present  in  the  particular  case. 

175 


I76  THE  SINUS  SPHENOIDALIS 

The  average  sphenoidal  sinus  of  the  term  fetus  has  a  capacity  of 
from  6  to  8  cubic  mm.,  measuring  approximately  2  by  2  by  i.  5  mm.  The 
ostium  sphenoidale  varies  in  diameter  from  0.5  to  1.5  mm. 

THE  CHILDHOOD  STAGE 

Even  in  infancy  the  sphenoidal  sinus  continues  to  be  nasal  in  position 
rather  than  sphenoidal.  However,  by  the  end  of  the  third  year  the  rudi- 
ment of  the  sphenoidal  sinus  is  surrounded  by  bone  save  ventrally  toward 
the  nasal  fossa  where  an  opening,  the  primitive  ostium  sphenoidale, 
exists.  During  the  fourth  year  the  superior  and  medial  parts  of  the 

Sinus  splu-nn'ulalis v 

Hypophysis 


PIG.  132. — A  sagittal  section  through  the  sphenoidal  sinus  of  a  child  aged  18  months.  Particu- 
larly note  that  the  sphenoidal  sinus  does  not  occupy  any  portion  of  the  sphenoid  bone  proper  at 
this  age,  but  is  distinctly  related  to  the  sphenoidal  concha  or  ossicle  of  Bertin.  X  0.9. 

bordering  nasal  capsule  are  resorbed  and  the  body  of  the  sphenoid  bone 
allowed  for  the  first  time  to  bound  the  terminal  nasal  sinus  (the  primitive 
sphenoidal  sinus).  The  superior  and  lateral  parts  of  the  sphenoidal 
concha  (bony  capsule)  are  also  resorbed.  This  resorption  causes  the 
ostium  sphenoidale  in  the  sphenoidal  turbinal  to  be  notched  instead  of 
rounded.  Later  the  inferior  part  and  those  portions  partially  surrounding 
the  ostium  sphenoidale  of  the  turbinal  in  question  fuse  with  the  ethmoid 
bone  and  the  body  of  the  sphenoid  bone.  This  gives  the  primitive 
sphenoidal  sinus  (sinus  terminalis)  opportunity  to  grow  into  and  pneu- 


CHILDHOOD  STAGE  177 

matize  the  body  of  the  sphenoid  bone  in  the  production  of  the  definitive 
sphenoidal  sinus. 

The  sphenoidal  sinus  in  early  childhood  is  more  precocious  than  one 
would  infer  from  divers  statements  in  the  literature.  It  is  well  known  that 
in  its  initial  growth  into  the  body  of  the  sphenoid  bone  the  sinus  has  a 
marked  tendency  to  develop  in  the  dorsolateral  plane  at  the  expense  of 
its  direct  ventrodorsal  growth.  This  leads  to  an  early  thinning  of  the 
lateral  wall  of  the  sinus  and  to  relatively  thick  septal  and  dorsal  walls. 
Indeed,  the  dorsolateral  aspect  of  the  sphenoidal  sinus  may  thus  early 
come  into  intimate  relationship  with  the  ophthalmic  and  maxillary  nerves 
and  be  a  potent  factor  in  childhood  neuralgias  of  the  trigeminal  nerve, 


FIG.   133. — A  frontal  section  through  the  nasal  fossae  and  sphenoidal  sinuses  of  a  child  aged  7  years. 

X  0.8. 

even  as  early  as  the  third  year.  Moreover,  the  pterygoid  (Vidian)  canal 
with  its  contained  nerve  and  vessels  likewise  early — sixth  or  seventh 
years — establish  close  relationship  with  the  developing  sphenoidal  sinus 
(see  page  320).  It  is  obvious  that  the  sphenoidal  sinus  is  early  of  im- 
portance clinically  and  that  by  the  second  or  third  year  has  assumed 
proportions  sufficiently  large  to  become  the  seat  of  pathologic  processes 
and  to  retain  infectious  material  in  its  cavity.  Table  I  indicates  the 
growth  of  the  sphenoidal  sinus  during  the  childhood  period,  e.g.,  from 
birth  to  puberty. 

The  distance  of  the  ostium  sphenoidale  from  the  cribriform  plate 
of  the  ethmoid  bone  varies  from  2  to  5.5  mm.  There  is  no  constancy 
in  size  of  the  ostium,  the  writer  finding  it  to  vary  from  i  X  i  mm.  to 


i78 


THE  SINUS  SPHKXOIDALIS 


3-o  X  3.5  mm.  in  a  limited,  but  graded  series  of  specimens  of  the  childhood 
stage. 


TABLE  I 


In  millimeters 

Age 

Side 

Cephalocaudal 
(height) 

Mediolateral 
(width) 

Ventrodorsal 
(length) 

ist  yr. 

R 

2-5 

2-5 

-5 

L 

2-5 

2-5 

.8 

2nd  yr. 

R 

4.0 

3-4 

.O 

L 

4.0 

3-5 

.0 

3rd  yr. 

R 

5-5 

4.0 

•  5 

L 

5-2 

4-0 

.8 

5th  yr. 

R 

7.0 

6-5 

4-5 

L 

6-5 

6.8 

4.8 

7th  yr. 

R 

II.  0 

7-5 

8.0 

L 

II  .0 

7.0 

7.0 

Qth  yr. 

R 

15.0 

12.0 

10.  o 

L 

M-5 

"•5 

II  .0 

nth  yr. 

R 

14.0 

13.0 

16.0 

L 

8-5 

10.  0 

8-5 

1  4th  yr. 

R 

15.0 

10.  0 

12.0 

L 

14.0 

14.0 

8.0 

THE  ADULT  STAGE 

General  Considerations. — The  adult  sphenoidal  sinus  occupies  a 
more  or  less  central  position  in  the  skull  and  varies  to  an  unusual  degree 
in  size  and  shape.1  It  is  commonly  located  in  the  ventral  and  cephalic 
part  of  the  body  of  the  sphenoid  bone.  However,  very  frequently  the 
paired  sinuses  pneumatize  the  entire  sphenoidal  body,  even  extend  into  the 
basilar  process  of  the  occipital  bone  and  into  the  pterygoid  processes  and 
lesser  wings  of  the  sphenoid.  Moreover,  the  sinuses  not  infrequently  extend 
in  the  form  of  recesses  into  the  superomedian  aspect  of  the  orbit,  especially 
into  the  orbital  process  of  the  palatal  bone  (palatal  sinus),  into  the  anterior 
and  posterior  clinoid  processes  and  bases  of  the  greater  wings  of  the  sphenoid 
bone  and  into  the  ethmoid  bone.  Of  course,  not  all  of  the  recesses  are 
necessarily  present  in  the  same  specimen.  Frequently  there  is  marked 
asymmetry,  giving  rise  to  a  prominent  recess  into  one  or  other  neighboring 
point.  Rarely  the  rostrum  of  the  sphenoid  is  invaded. 

The  recesses  of  the  sphenoidal  sinus  are  of  great  clinical  importance 
since  they  encroach  variously  upon  the  foramen  rotundum  with  the  con- 
tained maxillary  nerve;  the  foramen  ovale  with  the  mandibular  nerve; 

1  The  plaster  casts  of  the  sphenoidal  sinuses  by  Dr.  Hanau  W.  Loeb  are  valuable  and  instructive 
in  this  connection.  The  reader  is  referred  to  Dr.  Loeb's  Operative  Surgery  of  the  Nose,  Throat  and 
Ear,  St.  Louis,  1917. 


ADULT  STAGE  179 

and  the  superior  orbital  (sphenoidal)  fissure  with  the  ophthalmic,  oculo- 
motor, trochlear  and  abducent  nerves,  etc.  (Fig.  195).  When  the  lesser 
wing  and  the  anterior  clinoid  process  are  partially  hollowed  out,  the 
sphenoidal  sinus  encroaches  upon  the  optic  nerve,  and  if  the  pneumatiza- 
tion  is  extensive  the  nerve  lies,  in  a  sense,  within  the  cavity  of  the  sphe- 
noidal sinus.  The  clinical  importance  of  this  relationship  cannot  be  over- 
estimated (Figs.  140  and  197).  Very  frequently,  indeed,  the  body  of  the 
sphenoidal  sinus  is  so  hollowed  out  toward  and  into  the  bases  of  the 
pterygoid  processes  that  the  pterygoid  or  Vidian  canal  with  the  contained 
nerve  (Vidian)  and  vessels  throw  the  floor  of  the  sinus  into  a  ridged  relief. 
In  many  cases  the  nerve  and  vessels  are  separated  from  the  mucous  mem- 
brane of  the  sinus  by  the  merest  shell  of  bone.  Indeed,  osseous  dehiscences 
may  be  present  (Figs.  139  and  195). 

The  author  has  encountered  not  a  few  cadavers  in  which  the  sphe- 
noidal sinus  not  only  pneumatized  the  entire  ventral  portion  of  the  body 
of  the  sphenoid  bone,  but  extended  beyond  into  the  palate  and  ethmoid 
bones  in  the  formation  of  palatine  and  ethmoidal  recesses.  Indeed,  in  a 
number  of  instances  one  or  more  posterior  ethmoidal  cells  were  entirely 
replaced  by  such  sphenoidal-sinus  extensions.  The  latter  may  be  suf- 
ficiently extensive  to  be  bounded  by  the  ethmoid,  palate  and  maxillary 
bones  and  to  establish  immediate  relationship  with  the  maxillary 
sinus — a  shell-like  lamella  of  bone  alone  intervening  between  the  mucous 
membranes  of  the  respective  sinuses  (Figs.  135  and  136).  Rarely  the 
sphenoidal  sinus  extends  sufficiently  far  into  the  pterygoid  process  of  the 
sphenoid  bone  to  come  in  contact  with  the  wall  of  the  maxillary  sinus. 
Rarely  the  ethmoidal  extension  of  the  sphenoidal  sinus  is  found  to  be  in 
actual  contact  with  the  supraorbital  extension  of  the  frontal  sinus. 

The  ptery  go  palatine  (sphenomaxillary)  fossa  intervenes  between  the 
osseous  boundaries  of  the  sphenoidal  and  maxillary  sinuses  and  precludes 
intimate  relationships  between  the  two  sinuses  at  this  point,  and  any 
extension  of  the  sphenoidal  sinus  to  come  into  contact  with  the  maxillary 
sinus  must  either  be  over  the  sphenopalatine  fossa,  then  in  front  of  it, 
or  dorsal  and  inferior  to  the  fossa,  as  is  the  case  when  the  pterygoid  process 
is  hollowed  out.  The  pterygopalatine  fossa  is  normally  the  angular 
interval  between  the  pterygomaxillary  and  the  inferior  orbital  fissures, 
and,  as  stated  above,  occupies  the  space  between  the  maxilla  in  front  and 
the  root  of  the  pterygoid  process  behind.  Medially  the  perpendicular 
plate  of  the  palate  bone  and  nasal  mucous  membrane  separate  the  fossa 
from  the  nasal  cavity.  However,  the  osseous  medial  wall  is  deficient, 
containing  as  it  does  the  sphenopalatine  foramen.  The  latter  lies  between 


l8o  THE  SINUS  SPHENOID ALIS 

the  orbital  and  sphenoidal  processes  of  the  palate  bone  and  the  inferior 
surface  of  the  body  of  the  sphenoid.  The  roof  of  the  sphenopalatine 
fossa  is  formed  by  the  inferior  surface  of  the  body  of  the  sphenoid  and 
the  orbital  process  of  the  palate  bone.  The  fossa  contains  on  its  dorsal 
wall  the  orifices  of  the  pharyngeal  canal,  the  pterygoid  canal  (Vidian) 
and  the  foramen  rotundum,  from  within  outward.  Caudally  the  fossa 
contains  the  superior  opening  of  the  pterygopalatine  canal  together  with 
the  orifices  of  lesser  palatine  canals  (Figs.  135  and  145). 

The  sphenopalatine  fossa  with  its  contained  sphenopalatine  (nasal, 
Meckel's)  ganglion  is  obviously  very  intimately  related  with  certain 
of  the  paranasal  chambers  which  pneumatize  the  aforementioned  osseous 
boundaries.  Practically  always  the  sphenoidal  sinus  is  located  immediately 
over  the  fossa  and  the  ganglion,  and  when  the  sphenoidal  sinus  extends 
recess-like  into  the  pterygoid  process  it  gains  an  intimate  dorsal  relation- 
ship as  well.  Again,  when  the  sphenoidal  sinus  extends  forward  into 
the  ethmoid  bone  and  orbital  process  of  the  palate  bone  there  may  be 
even  a  sphenoidal-sinus  relationship  to  the  sphenopalatine  fossa  ventrally. 
Usually,  however,  the  maxillary  sinus  and  one  or  more  posterior  ethmoid al 
cells  are  the  paranasal  chambers  related  ventrally  to  the  sphenopalatine 
fossa  with  its  contained  ganglion.  It  is,  therefore,  very  clear  that  the 
sphenopalatine  ganglion  is  continually  subjected  to  the  influences  of  the 
very  intimately  related  paranasal  sinuses,  particularly  the  sphenoidal. 
The  nasal  fossa  is,  of  course,  in  constant  relationship  (Fig.  195). 

Not  infrequently  a  posterior  ethmoidal  cell  (or  cells)  grows  into  the 
body  of  the  sphenoid  bone  at  the  expense  of  one  or  both  sphenoidal  sinuses; 
indeed,  may  largely  or  entirely  replace  one  or  both  of  them.  Such  eth- 
moidal extensions  into  the  body  of  the  sphenoid  bone  are,  however,  readily 
distinguished  from  true  sphenoidal  sinuses  since  they  never  communicate 
with  the  sphenoethmoidal  recess — the  constant  position  for  the  aperture 
of  the  sphenoidal  sinus  (ostium  sphenoidale).  These  ethmoidal-cell  ex- 
tensions into  the  sphenoid  bone  may  be  referred  to  as  ethmosphenoidal 
cells.  The  cells  at  times  overlie  the  sphenoidal  sinuses  so  that  the  latter 
appear  in  sections  as  duplicated  or  triplicated  (Fig.  141).  The  location 
of  the  ostia  is,  of  course,  the  deciding  factor  in  the  classification.  More- 
over, it  is  especially  the  uppermost  of  such  posterior  ethmoidal  cells 
that  come  into  such  very  intimate  relationship  with  the  optic  nerve, 
optic  commissure,  and  even  with  the  hypophysis  cerebri  (Fig.  155). 

The  Topography  of  the  Adult  Sphenoidal  Sinus. — The  paired  sphe- 
noidal sinus  is  located  in  what  maybe  termed  the  danger  position  in  the  skull. 
Occupying  a  more  or  less  central  position  dorsal  to  the  cephalic  portion 


TOPOGRAPHY  OF  SPHENOIDAL  SINUS  181 

of  the  nasal  cavity,  it  comes  into  intimate  relationship  dorsally  with  the 
hypophysis  cerebri  and  not  infrequently  with  a  portion  of  the  brain  stem; 
laterally,  with  the  dural  cavernous  sinus  and  its  contained  and  related 
structures;  cephalically,  with  the  optic  commissure  and  frequently  with 
the  hypophysis  cerebri;  caudally,  with  the  Vidian  nerve,  the  choanse 
(posterior  nares),  and  the  nasopharynx;  ventrolaterally,  with  the  optic 
nerve  and  the  ophthalmic  artery.  The  relationships  of  the  optic  commis- 
sure and  the  hypophysis  cerebri  to  the  sphenoidal  sinus  are  variable  and 
dependent  upon  the  degree  of  pneumatization  of  the  body  of  the  sphenoid 
(vide  infra). 

The  ventral  wall  of  the  sphenoidal  sinus  projects  dorsalward  and 
caudalward,  forming  an  obtuse  angle  at  its  junction  with  the  cribriform 
plate  of  the  ethmoid.  The  wall  is  usually  relatively  thick  below  and 


Septum   ^'niMU'in,  spTienoidalivjn          Probe  in  ostium 


Sinus  sph.enoidodis    dextzr  *  -Sinus  sphcnoidalis   sinister 

PIG.  134. — A  sagittal  section  through  the  sphenoidal  sinuses.  Note  the  horizontal  position  of 
the  septum  of  the  sphenoidal  sinuses  and  that  the  sinuses  are  really  superior  and  inferior  to  each  other 
rather  than  right  and  left.  (Compare  with  Pigs.  141,  142  and  159.) 

frequently  of  extreme  delicacy  as  it  nears  the  cribriform  plate.  Clinically, 
the  ventral  wall  is  the  most  important  of  the  sinus  boundaries  because 
it  contains  the  aperture  of  the  cavity  (ostium  sphenoidale,  see  page  187). 
The  size  of  the  nasal  surface  of  the  ventral  wall  of  the  sphenoidal  sinus 
is  largely  dependent  upon  the  depth  of  the  sphenoethmoidal  recess.  When 
the  latter  is  deep  the  aperture  of  the  sinus  is,  as  a  rule,  farther  removed 
from  the  mid-sagittal  plane.  Posterior  ethmoidal  cells  and  the  dorsal 
extremities  of  certain  ethmoidal  conchae  bear  various  relationships  to  the 
ventral  wall.  By  following  the  olfactory  sulcus,  the  roof  of  the  nasal  fossa, 
and  the  upper  portion  of  the  ventral  sphenoidal  wall,  the  aperture  or 
ostium  of  the  sphenoidal  sinus  is  readily  located  (see  page  97). 

The  lateral  wall  of  the  sphenoidal  sinus  participates  in  bounding  the 
middle  cerebral  fossa  and  comes  into  immediate  and  direct  relationship 
with  the  dural  cavernous  sinus  and  the  contained  structures  (see  page  193). 


182  THE  SINUS  SPHENOIDALIS 

Moreover,  the  lateral  is  usually  one  of  the  thinnest  walls  of  the  cavity, 
often  reduced  by  extensive  pneumatization  to  a  papery  delicacy.  Indeed, 
osseous  dehiscences  are  not  infrequently  found.  In  surgical  procedures 
it  is,  therefore,  necessary  to  work  with  care  on  the  lateral  wall  of  the  sphe- 
noidal  sinus.  Curetting  seems  to  be  contraindicated  because  of  the  inti- 
mate relationships  with  the  cavernous  sinus  and  the  frequent  osseous 
defects,  whereby  the  sinus  mucosa  is  in  direct  contact  with  the  dural  wall 
of  the  vascular  sinus  (Figs.  195  and  197). 

The  dorsal  wall  of  the  sphenoidal  sinus  is  usually  relatively  thick  and 
less  subject  to  variation  as  compared  with  the  other  walls.  However, 
not  infrequently  one  encounters  specimens  in  which  the  sphenoidal  sinus 
has  pneumatized  beneath  and  dorsal  to  the  sella  turcica,  leading  to  an 
extremely  thinned-out  dorsal  wall.  This  variation  must  be  borne  in 
mind  in  operative  procedures,  because  the  wall  is  readily  broken  through, 
and  the  basilar  artery  and  pons  immediately  dorsal  subjected  to  injury 
(Figs.  175  and  195).  Further  mention  will  be  made  of  this  relationship  in 
connection  with  the  hypophyseal-sphenoidal  relations  (page  188). 

The  cephalic  wall  of  the  sphenoidal  sinus  is  extremely  variable  in  its 
contour,  thickness  and  extent.  It  is  usually  composed  of  thin,  compact 
bone;  however,  may  contain  a  considerable  amount  of  cancellated  bone 
between  two  compact  lamellae.  The  contour  and  extent  of  the  cephalic 
wall  are  largely  dependent  upon  the  degree  of  pneumatization  of  the  sphe- 
noid bone  and  the  shape,  position  and  size  of  the  sella  turcica  (Figs.  146  and 
154).  Moreover,  osseous  defects  are  occasionally  encountered  whereby 
the  sinus  mucosa  and  the  ectal  layer  of  the  dura  mater  are  in  actual  con- 
tact. Conforming  with  the  size  of  the  sphenoidal  sinus,  the  relations  of 
the  intracranial  structures  vary.  However,  the  hypophysis  cerebri  and 
the  optic  commissure  are  fairly  constant  in  some  form  of  relationship 
to  the  cephalic  wall  (see  page  188). 

The  caudal  wall  of  the  sphenoidal  sin  us  has  its  mid-point  approximately 
over  the  choana  (posterior  naris),  being  half  nasal  and  half  pharyngeal  in 
location.  Not  infrequently,  owing  to  marked  asymmetry,  one  or  the 
other  sphenoidal  sinus  is  superimposed  over  both  the  right  and  left  choanse 
or  posterior  nares  (Fig.  135).  It  varies  from  2  to  13  mm.  in  thickness, 
according  to  a  series  of  specimens  investigated.  This  wall  was  at  one 
time  used  as  an  approach  to  the  sphenoidal  sinus,  via  the  buccal  cavity. 
The  ascending  palatine  artery  (a.  palatina  ascendens,  pharyngo-palatine 
artery),  a  branch  of  the  external  maxillary  (facial)  artery,  crosses  the 
lateral  angle  of  the  ectal  surface  of  the  caudal  wall  of  the  sphenoidal  sinus 
and  is  here  endangered  in  surgical  procedures  in  the  neighborhood.  The 


OSSEOUS  SEPTA  AND  RECESSES  183 

floor  of  the  sphenoidal  sinus  may  be  so  hollowed  out  that  the  nerve  of  the 
pterygoid  canal  (Vidian  nerve)  is  at  best  separated  from  the  sinus  mucosa 
by  a  tissue-like  plate  of  bone.  Indeed,  as  stated  elsewhere,  the  osseous 
canal  may  be  defective  here  and  there,  thereby  exposing  the  Vidian  nerve 
and  vessels  to  the  direct  influences  of  the  outside  air  (Fig.  195).  See 
also  page  320  for  a  consideration  of  the  Vidian  nerve. 

Not  infrequently  in  the  extension  of  the  sphenoidal  sinus  into  the 
pterygoid  process  of  the  sphenoid  bone  and  into  the  perpendicular  plate 
of  the  palate  bone  and  the  lateral  mass  of  the  ethmoid  bone  there  is  marked 
encroachment  upon  the  confines  of  the  pterygopalatine  fossa  (see  page 
318)  with  its  contained  structures,  e.g.,  the  sphenopalatine  ganglion,  etc. 

The  medial  wall  of  the  sphenoidal  sinus  is  the  inter-sinus  septum  re- 
ferred to  on  page  187.  Dehiscences  of  this  wall  have  been  reported; 
however,  the  author  encountered  no  such  defect  in  a  large  series  of  healthy 
specimens.  The  medial  wall  is  usually  asymmetrical  in  location  and  not 
infrequently  inclines  in  a  semi-horizontal  plane  instead  of  its  more  usual 
vertical  and  semi-sagittal  position  (Figs.  134,  135,  and  159). 

Partial  Osseous  Septa  and  Recesses  of  the  Sphenoidal  Sinus.— 
While  it  is  true  that  many  sphenoidal  sinuses  have  even  and  regular  in- 
terior osseous  walls,  it  is  equally  true  that  of  all  the  paranasal  sinuses  the 
sphenoidal  presents  with  the  greatest  frequency  the  most  irregular  walls 
(Fig.  195).  Crescentic  partial  osseous  septa  are  extremely  commonplace. 
These  vary  from  slight  elevations  to  bridge-like  osseous  barriers  which 
incompletely  divide  the  sinus  into  subcompartments.  Indeed,  these 
septa  are  at  times  very  misleading  in  sections  of  the  sphenoidal  sinus, 
since  multiple  sinuses  are  simulated  in  certain  planes  of  section.  Serial 
sections,  of  course,  demonstrate  the  true  anatomy;  that  is,  that  the  septa 
are  incomplete  and  but  partially  divide  the  sinus.  The  irregularities 
form  recesses  which  in  many  cases  obviously  must  retain  infectious  material 
despite  the  establishment  of  good  drainage  surgically.  In  some  cases  it 
would  seem  necessary  to  break  down  some  of  the  recesses.  However,  the 
operator  must  bear  in  mind  that  these  recesses  and  diverticula  often  have 
extremely  thin  outer  walls  and  that  there  is  danger  of  spreading  the  infec- 
tion intracranially  and  intraorbitally  by  breaking  into  these  cavities. 
Moreover,  related  structures  are  endangered  (see  elsewhere). 

As  stated  elsewhere,  entirely  apart  from  the  recesses  formed  by  the 
very  common  partial  osseous  septa  the  sphenoidal  sinus  not  infrequently 
pneumatizes  extensively  into  the  greater  and  lesser  wings  of  the  sphenoid, 
into  the  orbital  plate  of  the  palate  bone,  into  the  ethmoid  bone  and  into 
the  pterygoid  process.  Recess  extensions  into  the  pterygoid  processes  are 


1 84  THE  SINUS  SPHENOID ALIS 

always  fraught  with  danger  since  they  form  deep  pockets  in  the  floor  of 
the  sphenoidal  sinus  and  cause  the  dependent  portion  of  the  sinus  floor  to 
be  still  farther  from  the  aperture  of  the  sphenoidal  sinus  (Fig.  139).  As 
stated  elsewhere,  the  aperture — ostium  sphenoidale — is  at  best  very  dis- 
advantageously  located  for  efficient  drainage  and  in  this  regard  parallels 
the  ostium  of  the  maxillary  sinus,  e.g.,  the  ostium  maxillare. 

Sphenoidal  Sinus  Diverticula. — Diverticula  of  the  sphenoidal  sinus 
may  be  divided  into  two  groups:  (i)  the  recess-like  extensions  of  the 
sphenoidal  sinus  into  outlying  portions  of  the  sphenoid  bone  and  into 
bordering  bones,  the  osseous  boundaries  of  such  diverticula  or  recesses 
being  complete;  (2)  mucosal  diverticula  or  evaginations  through  dehis- 
cences  in  the  osseous  wall  of  the  sphenoidal  sinus,  the  osseous  boundaries 
of  such  diverticula  being  wanting. 

1.  The  recess-like  extensions  of  the  sphenoidal  sinus  in  which  muco- 
periosteum  and  bone  participate  as  boundaries  were  referred  to  in  the 
previous  paragraph  and  will  be  dealt  with  at  greater  length  in  subsequent 
paragraphs.     They  can,  therefore,  be  ignored  in  this  connection. 

2.  Zuckerkandl,  Onodi,  Spec,  Meyer  and  others  have  reported  defects 
in  the  osseous  lateral  wall  of  the  sphenoidal  sinus.     The  writer  likewise 
made  similar  observations  and  reported  at  length  concerning  them  at 
an  Anatomical  Seminar  at  Cornell  University  in  1910.     Many  of  these 
defects  or  dehiscences  merely  lead  to  such  a  condition  whereby  the  mucous 
membrane  of  the  sphenoidal  sinus  comes  in  direct  contact  with  the  ectal 
layer  of  the  dura  mater.     At  times,  however,  the  mucous  membrane 
evaginates  hernia-like  through  an  osseous  defect  or  dehiscence.     The 
author  observed  two  such  specimens  in  the  Cornell  University  collection 
and  a  third  in  the  Yale  University  collection.     All  three  were  unilateral. 
These  mucosal  diverticula  or  herniae  protruded  for  variable  distances — 
3.5  and  5.5  mm. — into  the  epidural  space  by  crowding  the  dura  mater 
ahead  of  them.     One  of  the  mucosal  diverticula  projected  into  the  cav- 
ernous sinus  by  pushing  the  ectal  or  outer  layer  of  the  dura  mater  bag-like 
into  the  lumen  of  the  sinus. 

Meyer  observed  a  specimen  in  which  there  was  a  defect  in  the  ventral 
portion  of  the  lateral  wall  of  the  right  sphenoidal  sinus  immediately  be- 
neath its  roof.  Through  this  osseous  opening,  oval  in  shape,  protruded 
a  diverticulum  of  the  sinus  mucosa,  6  mm.  long,  into  the  subdural  space. 
The  wall  of  the  diverticulum  was  exceedingly  thin  and  extended  forward 
and  upward  into  a  triangular  space  bounded  by  the  optic  nerve  antero- 
medially,  the  carotid  artery  posteromedially  and  the  reflection  of  the  dura 
mater  laterally.  The  dura  surrounded  the  base  of  the  diverticulum  on 


DIVERTICULA  185 

all  sides  but,  contrary  to  the  author's  specimens,  did  not  envelop  or  cover 
the  mucosal  fundus.  The  dura  merely  came  in  contact  with  the  mucosa 
at  the  margin  of  the  osseous  defect.  In  other  words,  the  dura  mater  as 
well  as  the  bone  was  deficient,  permitting  the  sphenoidal-sinus  mucous 
membrane  to  protrude  through  them.  The  mucous  membrane  or  the 
sphenoidal  diverticulum  extended,  thereby,  directly  into  the  subdural 
space  and  must  have  been  in  direct  contact  with  the  arachnoid. 


Rrameit  ?naujrivu,m 


.  >~  - 

Sinus  spltcwufales  .."V  '.<*;:  .., 


Sep.sinuum  spkenoidal 
S.  ntaxillaris 


FIG.  135. — A  basal  dissection  of  the  sphenoidal  and  maxillary  sinuses.  Particularly  note  that 
the  right  sphenoidal  sinus  has  pneumatized  forward  into  the  ethmoidal  region  and  established  an 
immediate  relationship  with  the  maxillary  sinus,  a  thin  lamella  of  bone  alone  intervening.  Note 
also  the  asymmetry  of  the  sphenoidal  sinuses. 

The  ventral  half  of  the  lateral  wall  of  the  left  sphenoidal  sinus  con- 
tained a  similar  defect  to  that  in  the  right  sinus.  A  diverticulum  of 
mucous  membrane  protruded  through  the  oval  defect  for  a  distance  of 
3.5  mm.  and  extended  across  the  dural  reflexions  over  the  optic  and  oculo- 
motor nerves  and  enlarged  slightly  distally.  The  relations  of  the  diver- 
ticulum to  the  surrounding  structures  were  exactly  the  same  as  in  the 
diverticulum  from  the  right  side.  The  diverticulum  measured  6  mm. 
in  length  and  7  mm.  in  width. 


186 


THE  SINUS  SPHENOIDALIS 


Surely  dura  mater  must  have  covered  these  diverticula  at  the  time 
of  their  initial  outgrowth  from  the  sphenoidal  sinus.  However,  at  the 
time  of  observation  the  dura  mater  was  perforated  and  the  diverticula 
in  actual  relationship  with  the  arachnoid.  Why  the  dura  mater  should  be 
perforated  is,  indeed,  difficult  to  explain.  The  more  likely  thing  would 
seem  for  the  dura  to  be  pushed  in  advance  of  the  evaginating  diverti- 


Fossa  sacci  lacriinalis 

,Cc.  ethmoideiles 

Sinus  mazillaris 


a,  of  bone  between 
s~ph.enoid.al  ajid  maxillary 


Foramen,    rotnnduttt 
sp~henoidodis 

PIG.  136. — A  dissection  showing  a  marked  extension  of  the  sphenoidal  sinus  forward  into  the 
ethmoidal  field,  replacing  certain  posterior  ethmoidal  cells,  to  come  into  immediate  relationship  with 
the  maxillary  sinus.  This  unusual  relationship  is  of  importance  clinically. 

cula.  Of  course,  the  basal  dura  mater  is  extremely  adherent  and  in  all 
likelihood  is  perforated  with  greater  ease  by  the  growing  mucosal  sac  than 
crowded  away  from  its  bony  attachments. 

Clinically,  dehiscences  in  the  osseous  wall  of  the  sphenoidal  sinus 
are  significant  and  when  such  defects  lead  to  mucosal  diverticula  (in  a 
sense,  mucosal  herniae),  which  come  in  relationship  anatomically  with  the 


SPHENOIDAL  SEPTUM  AND  OSTIUM  187 

subdural  space  and  the  dura  and  arachnoid  maters,  they  become  even 
more  important. 

The  Sphenoidal  Septum  (the  septum  sinuum  sphenoidalium)  .— 
The  paired  sphenoidal  sinuses  are  separated  by  a  septum  of  variable 
thickness  and  location.  The  thickness  is  largely  dependent  upon  the 
degree  of  pneumatization  or  size  of  the  sinuses.  The  intersphenoidal 
septum  may  be  placed  more  or  less  vertical  and  in  the  median  plane 
throughout.  More  frequently,  however,  it  is  placed  either  to  the  right 
or  to  the  left  of  the  mid-sagittal  plane,  save  ventrally  where  it  is  usually 
in  line  with  the  septum  nasi.  This  leads  to  asymmetrical  sphenoidal 
sinuses.  Indeed,  the  septum  may  be  placed  obliquely  in  a  semi-horizontal 
plane  so  that  the  right  and  left  sinuses  are  in  a  sense  cephalic  and  caudal 
in  relation  to  each  other.  According  to  the  writer's  studies,  the  sphe- 
noidal sinuses  never  normally  communicate  with  each  other  due  to  a  de- 
fective septum.  However,  such  communications  have  been  observed  in 
pathologic  states. 

A  few  cases  have  been  reported  in  which  the  inter-sinus  septum  was 
believed  to  be  wholly  absent,  the  two  sinuses  being  represented  by  one 
large  cavity  with  a  single  ostium.  The  writer,  however,  questions  this 
interpretation  and  contends  that  the  real  condition  is  an  agenesis  of 
one  sinus,  thus  allowing  the  single  sinus  to  develop  beyond  the  mid-line 
in  pneumatizing  the  body  of  the  sphenoid.  The  single  ostium  supports 
this  view.  Indeed,  it  is  not  uncommon  for  one  sinus  to  be  enormously 
developed  and  for  its  mate  to  be  a  mere  rudiment.  The  latter  might 
lead  to  the  belief  that  the  sinus  is  wholly  wanting.  Careful  analysis, 
however,  usually  reveals  the  diminutive  sinus  (Figs.  134,  136,  141, 
143,  144  and  159). 

The  Sphenoidal  Ostium. — The  sphenoidal  ostium  (ostium  sphenoidale) 
or  orifice  of  the  sphenoidal  sinus  is  always  located  on  the  dorsal  wall  of 
the  sphenoethmoidal  recess,  therefore,  cephalic  to  the  uppermost  eth- 
moidal  concha  that  may  be  present.  The  right  and  left  ostia  are  not 
necessarily  on  the  same  level.  They  are  in  most  cases  located  slightly 
cephalic  to  the  mid-plane  of  the  ventral  wall  of  the  sinuses.  There  is, 
however,  often  marked  deviation  from  this  location  as  may  be  inferred 
from  the  measurements  (in  millimeters)  given  in  Table  J  of  a  number  of 
specimens  selected  from  a  larger  series: 

It  is  obvious  from  the  following  table  that  the  ostium  of  the  sphenoidal 
sinus  is  very  disadvantageously  placed  for  efficient  drainage  in  case  of 
empyema  of  the  cavity. 


1 88 


THE  SINUS  SPHENOIDALIS 
TABLE  J 


Side 

Distance  from  center  of  ostium  sphe- 
noidale  to  roof  of  sinus 

Distance  from  center  of  ostium  sphe- 
noidale  to  floor  of  sinus 

R 

12 

17 

L 

10 

13 

R 

12 

12 

L 

12 

9 

R 

2 

'3 

L 

16 

13 

R 

2 

20 

L 

12 

T7 

R 

3 

6 

L 

12 

4 

R 

15 

17 

L 

17                                                               16 

Size  of  Sphenoidal  Sinus. — The  appended  Table  K  of  measurements 
(in  millimeters)  of  a  few  specimens  selected  from  a  larger  series  shows  the 
great  variation  in  size  of  the  sphenoidal  sinus.  Extremely  rudimentary 
sinuses  are  encountered ;  again,  enormous  pneumatizations  of  the  sphenoid 
bone  are  not  uncommon,  even  extending  beyond  the  body  of  the  bone 
(Figs.  136  and  143). 

TABLE  K 


Cephalocaudal 
(height) 


Mediolateral 
(width) 


Ventrodorsal 
(length) 


r 

R 

27 

32 

3° 

L 

21 

28 

28 

R 

5 

3 

3 

2 

L 

25 

18 

20 

R 

20 

16 

17 

3 

L 

18 

10 

14 

R 

34 

14 

18 

4 

L 

35 

27 

35 

R 

10 

9 

9 

5 

L 

21 

27 

22 

6      ' 

R 

19 

12 

18 

L 

8 

6 

7 

R 

26 

27 

3° 

7 

L 

16 

12 

20 

Q            J 

23 

34 

43 

11     L 

32 

28 

37 

Averages 

21  .  2 

18.9 

21.3 

Conforming  with  the  variations  in  size,  the  capacity  of  the  sphenoidal 
sinus  was  found  to  vary  from  less  than  0.5  cm.  to  30  cm.,  with  an  ap- 
proximate average  of  about  7.5  cm. 

The  Hypophysis  Cerebri  as  Related  to  the  Sphenoidal  Sinus. — The 
hypophysis  cerebri   (pituitary  body)  is  a  small  ovoid  gland,  flattened 


HYPOPHYSIS  CEREBRI  189 

cranio-caudally,  and  with  its  long  axis  directed  transversely.  It  occupies 
the  rnpophyseal  fossa  (fossa  hypophyseos,  sella  turcica),  a  deep  depres- 
sion over  the  middle  of  the  superior  (cephalic)  surface  of  the  body  of  the 
sphenoid  bone.  Dorsally  the  hypophyseal  fossa  is  overhung  by  a  sloping 
ridge,  the  dorsum  sellae,  and  ventral  to  the  fossa  is  the  olivary  eminence 
(tuberculum  sellae).  The  hypophysis  is  roofed  over  by  a  spheroid  pocket 
of  dura  mater — the  diaphragma  sellae.  The  latter  separates  the  hypo- 
physis from  the  optic  commissure  and  the  optic  tracts,  which  lie  im- 
mediately cephalic  (above)  to  it.  The  stalk  (infundibulum)  of  the  hypo- 
physis penetrates  the  dura  mater  dorsal  to  the  optic  commissure  and 
midway  between  the  optic  tracts.  Laterally  the  cavernous  sinus  with 
the  contained  internal  carotid  artery  comes  into  relationship  with  the 
hypophysis  and  the  sphenoidal  sinus. 

The  exact  relations  of  the  hypophysis  to  the  sphenoidal  sinuses  must 
necessarily  vary,  since  the  shape  and  size  of  the  sinuses  are  inconstant 
(Figs.  143,  146  and  175).  In  many  cases  the  hypophysis  is  dorsal  (posterior) 
to  the  sphenoidal  sinuses  and  located  much  nearer  the  sinus  roof  than  the 
floor.  Not  infrequently,  however,  the  sphenoidal  sinuses  pneumatize 
the  body  of  the  sphenoid  bone  caudal  (beneath)  and  dorsal  to  the  hypo- 
physeal fossa.  When  the  latter  anatomy  prevails  the  hypophysis  bears 
a  dorsocephalic  relationship  to  the  sphenoidal  sinuses.  The  thickness  of 
the  bone  intervening  between  the  sinuses  and  the  hypophysis  varies  with 
the  size  and  location  of  the  sinuses. 

The  hypophysis  may  be  exposed  by  an  endonasal  operation  through 
the  sphenoidal  sinuses  after  first  removing  the  ventral  wall  and  the  septum 
of  the  sinuses.  Of  course,  when  the  sinuses  are  markedly  asymmetrical, 
the  removal  of  the  septum  may  not  be  necessary,  provided  the  operator 
selects  the  proper  sinus  in  the  approach.  In  order  to  expose  some  hypo- 
physes the  dorsal  wall  of  the  sinuses  should  be  ablated  immediately  caudal 
(inferior)  to  the  plane  where  the  roof  and  dorsal  walls  are  confluent  (Fig. 
146).  However,  when  the  sphenoidal  sinuses  have  developed  beneath  the 
hypophyseal  fossa  with  the  contained  hypophysis  cerebri  and  dorsad 
toward  (maybe  into)  the  basilar  process  of  the  occipital  bone,  it  is  the  roof 
and  not  the  dorsal  wall  of  the  sphenoidal  sinuses  that  must  be  ablated 
in  order  to  expose  the  hypophysis  cerebri  (Fig.  195).  In  the  latter,  the 
anatomy  is  such  that  the  operator  could  readily  cut  through  the  dorsal 
wall  of  the  sinuses,  miss  the  hypophysis  altogether,  and  injure  the  basilar 
artery  and  brain  (pons).  Moreover,  the  operator  must  have  due  regard 
for  the  important  structures  located  lateral  to  the  hypophysis. 

It  is  not  the  province  here  to  discuss  the  detailed  embryology,  histol- 


I  QO  THE  SINUS  SPHENOIDALIS 

ogy  and  gross  anatomy  of  the  hypophysis  cerebri,  suffice  it  to  say  that 
it  consists  of  three  portions;  the  ventral,  dorsal  and  intermediate  portions. 
The  ventral,  glandular  or  buccal  lobe  usually  embraces,  cap-like,  the 
smaller  dorsal  or  cerebral  lobe.  The  dorsal  lobe  is  connected  by  means  of 
the  infundibulum  with  the  tuber  cinereum  in  the  floor  of  the  third  ventricle. 
The  latter  often  extends  canal-like  into  the  infundibular  stalk  for  a  con- 
siderable distance.  The  ventral  lobe  may  be  regarded  as  the  functional 
portion  of  the  hypophysis  and  the  portion  in  most  intimate  relationship 
with  the  sphenoidal  sinus. 

Tumors  of  the  hypophysis  cerebri  may  encroach  upon  the  lumina  of 
the  sphenoidal  sinuses,  even  penetrate  into  the  cavities.  Encroachment 
on  any  of  the  surrounding  structures  may  lead  to  serious  results. 

The  Optic  Nerve  and  Commissure  (chiasm)  as  Related  to  the  Para- 
nasal  (accessory)  Sinuses. — It  is  essential  that  the  intimate  anatomic 


2 

:       Cancdnpteryy/ndeus^Ldd) 
Canali 


FIG.  137.  FIG.   138.  FIG.   139. 

FIGS.  137,  138,  139. — In  Fig.  137  note  the  extension  of  the  sphenoidal  sinus  (dorsal  exposure) 
into  the  great  wing  of  the  sphenoid  bone  with  resultant  intimate  relations  to  the  foramina  rotundum 
(maxillary  nerve)  and  ovale  (mandibular  nerve).  Note  also  that  the  pterygoid  or  Vidian  canal  forms 
a  conspicuous  mound  in  the  floor  of  the  sphenoidal  sinus. 

In  Fig.  138  note  the  relations  of  the  foramen  rotundum  and  the  pterygoid  canal  when  the  sphe- 
noidal sinus  has  not  pneumatized  into  the  pterygoid  process  of  the  sphenoid  bone. 

In  Fig.  139  note  the  extensive  prolongation  of  the  sphenoidal  sinus  into  the  pterygoid  process  of 
the  sphenoid  bone  (recessus  pterygoideus) ,  with  a  resultant  wide  separation  of  the  foramen  rotundum 
and  the  pterygoid  canal  (ventral  exposure). 

The  inset  illustrates  the  superior  orbital  (sphenoidal)  fissure  with  contained  strictures.  6  = 
abducent  nerve;  4  =  trochlear  nerve;  5'  =  frontal  nerve;  5  =  lacrimal  nerve;  5"  =  nasal  nerve; 
3  =  inf.  div.  oculomotor  nerve;  3'  =  sup.  div.  oculomotor  nerve. 

relationships  which  exist  between  the  paranasal  sinuses  and  the  optic 
nerve  and  commissure  be  understood  by  ophthalmologists  and  rhinolo- 
gists.  It  is  established  that  disease  of  the  paranasal  sinuses  may  lead  to 
an  optic  neuritis,  even  to  blindness.  Of  the  paranasal  sinuses,  the  sphe- 


OPTIC  NERVE  AND  COMMISSURE 


191 


noidal  and  the  posterior  ethmoidal  especially  concern  us  in  this  connec- 
tion (Figs.  140  and  155). 

The  optic  nerve  in  its  course  from  the  eyeball  to  its  juncture  with  the 
optic  commissure  pursues  a  more  or  less  direct  course  dorsalward,  medial- 
ward,  and  cranial  ward  toward  the  apex  of  the  bony  orbit.  At  the  apex 
of  the  orbit  it  is  surrounded  by  the  origins  of  the  recti  muscles,  while  in  the 
orbit  it  is  embedded  by  orbital  fat.  It  traverses  the  optic  foramen  in  the 
sphenoid  bone  in  company  with  the  ophthalmic  artery — the  latter,  latero- 
caudal  in  relation  to  the  nerve.  Intracranially  the  optic  nerve  converges 
toward  its  fellow  of  the  opposite  side  with  which  it  forms  a  junction  to 
form  the  optic  commissure  in  the  vicinity  of  the  tuberculum  sellae  (oli- 
vary eminence).  The  optic  nerve  varies  from  32  to  55  mm.  in  length. 
Of  this  25  to  40  mm.  is  intraorbital  in  position  while  the  remaining  portion 
is  located  in  the  optic  foramen  and  the  anterior  cerebral  fossa. 

It  is  obvious  when  one  recalls  the  direction  of  the  optic  nerves,  far 
removed  from  each  other  distally  and  in  confluence  at  the  commissure,  that 
the  relations  to  the  paranasal  sinuses  become  more  and  more  intimate  as 
one  passes  from  the  eyeball  toward  the  optic  commissure.  Indeed,  for 
a  considerable  distance  from  the  eyeball,  the  optic  nerve  is  so  far  removed 
from  the  paranasal  sinuses  that  very  intimate  relationship  is  precluded 
by  the  intervention  of  a  considerable  mass  of  orbital  fat.  However,  as 
the  optic  nerve  approaches  the  orbital  apex  and  passes  through  the  optic 
foramen  to  the  optic  commissure,  very  intimate  relationships  exist  be- 
tween some  of  the  paranasal  sinuses  and  the  nerve  and  its  commissure 
(Figs.  140  and  145). 

The  optic  commissure  bears  a  very  intimate  relationship  to  the  sphe- 
noidal sinus  in  the  vast  majority  of  cases.  The  exact  relationships,  how- 
ever, vary  with  the  size,  shape,  symmetry,  and  location  of  the  sinuses. 
The  commissure  is  frequently  placed  immediately  cephalic  (above)  to 
the  roof  of  one  or  both  sinuses.  In  this  connection  it  is  well  to  recall  that 
asymmetry  is  commonplace  between  the  two  sphenoidal  sinuses.  The 
thickness  of  the  bone  intervening  between  the  sinuses  and  the  optic  com- 
missure varies  considerably,  e.g.,  from  a  papery  delicacy  to  that  of  a  sub- 
stantial thickness.  In  approximately  50  per  cent,  of  instances  the  optic 
commissure  lies  dorsal  (posterior)  in  relation  to  the  sphenoidal  sinuses. 
As  a  rule,  the  posterior  ethmoidal  cells  do  not  come  into  relationship  with 
the  optic  chiasm.  However,  when  the  posterior  ethmoidal  cells  grow 
into  the  body  of  the  sphenoid  bone  intimate  relationships  are  likewise 
established  (Figs.  155  and  162). 

The  optic  nerve  pursues  a  course  ventralward  from  the  optic  com- 


192 


THE  SINUS  SPHFA'OIDALIS 


missure  along  either  the  roof  or  lateral  wall  of  the  sphenoidal  sinus.  Fre- 
quently a  posterior  ethmoidal  cell  is  more  or  less  intimately  related  as  well. 
After  the  optic  nerve  passes  beyond  the  vicinity  of  the  posterior  ethmoidal 
cells,  it  diverges  more  and  more  from  the  ethmoidal  field  and  is  no  longer 
in  intimate  relationship  with  the  other  ethmoidal  cells. 

The  thickness  of  the  bone  between  the  optic  foramen  and  contained 
structures  and  the  cavity  of  the  sphenoidal  sinus  varies  according  to  the 
author's  studies  from  0.2  mm.  to  2  mm.,  with  an  average  of  not  over 
0.5  mm.  In  very  large  sphenoidal  sinuses  the  optic  nerve  joins  the  optic 


Jfit.oJfuctom  etlamiuci  cribrosa. 


C.efkmoidalis  post. 


N.  options  . 


,  Si.7iu>s  frcmfadis 

Cc  etkmoidodes  ant. 
Orbital  fat 


A.  car  o  UK  inter  no,' 

Hypophysis  cerebri, 

FIG.  140. — An  exposure  of  the  paranasal  chambers  from  the  anterior  cerebral  fossa.  Moreover, 
the  supraorbital  walls  have  been  removed,  thereby  exposing  the  optic  nerve  and  eyeball.  Particu- 
larly note  the  relationships  of  the  right  optic  nerve  and  that  the  sphenoidal  sinus  extends  beneath 
and  over  it,  a  thin  lamella  of  bone  alone  separating  the  nerve  from  the  sinus  mucosa.  On  the  left 
side  the  optic  nerve  bears  a  very  common  relationship  to  the  sphenoidal  sinus  and  a  posterior 
ethmoidal  cell. 

The  inset  is  a  photograph  of  a  transection  of  the  ethmoidal  labyrinth  and  sphenoidal  sinuses. 
Note  the  larger  number  of  individual  ethmoidal  cells  as  compared  with  the  main  figure. 

commissure  (chiasm)  in  the  roof  of  the  sphenoidal  sinus  some  distance  in 
advance  of  the  dorsal  wall  of  the  sinus.  This  may  apply  to  one  or  both 
sides.  Opposed  to  this,  in  small  sphenoidal  sinuses  the  optic  nerve  usu- 
ally joins  the  optic  commissure  dorsal  to  the  sphenoidal  sinuses  (Fig.  144). 
There  is  considerable  variation  in  the  distance  between  the  caudal 
surface  of  the  optic  nerve  and  the  ostium  sphenoidale.  The  two  sides 


CAVERNOUS  SINUS 


193 


in  this  regard  are  frequently  asymmetrical.  Usually  the  optic  nerve  is 
cephalic  to  the  level  of  the  ostium  sphenoidale.  They  may,  however,  be 
on  the  same  plane  or  the  reverse  relationship  may  obtain,  e.g.,  the  ostium 
be  cephalic  to  the  nerve.  It  is  not  uncommon  for  the  nerve  to  be  within 
2  to  5  mm.  of  the  ostium  of  the  sphenoidal  sinus.  Again,  a  distance  of  15 
or  more  millimeters  my  intervene.  The  nerve  is  never  more  than  a  few 
millimeters  caudal  to  the  ostium  of  the  sinus  when  such  relationship  exists. 

Occasionally  the  sphenoidal  sinus  almost  surrounds  the  optic  nerve. 
Witness,  for  example,  the  specimen  shown  in  Fig.  140  in  which  the  sphe- 
noidal sinus  has  developed  beneath  and  over  the  optic  nerve.  Lateral 
to  the  optic  nerve  the  two  sinus  extensions  are  separated  merely  by  a  thin 
lamella  of  bone.  Moreover,  the  nerve  is  separated  from  the  sinus  mucosa 
by  a  thin,  tubular  mass  of  compact  bone. 

As  mentioned  previously,  the  most  dorsal  of  the  posterior  ethmoidal 
cells  frequently  comes  into  intimate  relationship  with  the  optic  nerve. 
This  also  applies  with  less  frequency  to  the  other  posterior  ethmoidal 
cells  not  in  actual  contact  with  the  sphenoidal  sinus.  Not  infrequently 
two  or  more  posterior  ethmoidal  cells  are  in  immediate  relationship  with 
the  sphenoidal  sinus  instead  of  the  more  usual  single  cell.  These  cells 
may  be  arranged  tier-like  one  over  the  other,  the  uppermost  one  estab- 
lishing most  intimate  relations  with  the  optic  nerve  and  commissure 
(Fig.  145). 

The  frontal  sinus,  when  of  the  supraorbital  type  and  when  well 
developed  dorsomedially,  may  establish  close  relationships  with  the  optic 
nerve,  otherwise  the  latter  does  not  bear  important  relations  to  the  frontal 
sinus. 

The  maxillary  sinus  is  separated  from  the  optic  nerve  by  the  inter- 
vening osseous  boundary  and  by  a  considerable  amount  of  orbital  fat 
and  other  structures.  The  relationship  is,  therefore,  not  intimate  as  a 
rule. 

The  Cavernous  Sinus  and  Contained  Structures  as  Related  to  the 
Sphenoidal  Sinus. — The  cavernous  sinus  is  an  endothelially  lined  channel 
contained  within  the  dura  mater  and  is  traversed  by  irregular  trabeculae 
of  fibrous  tissue.  This  paired  vascular  sinus,  of  considerable  size,  extends 
along  the  lateral  side  of  the  body  of  the  sphenoid  bone  from  the  superior 
orbital  (sphenoidal)  fissure  to  the  apex  of  the  petrous  portion  of  the  tem- 
poral bone.  In  this  position  the  cavernous  sinus  with  its  contained  struc- 
tures is  in  intimate  relationship  with  the  sphenoidal  sinus.  The  internal 
carotid  artery  and  the  abducens  nerve  traverse  the  sinus,  while  the  oculo- 
motor, the  trochlear,  the  ophthalmic  and  the  maxillary  nerves  are  imbedded 

13 


194 


THE  SINUS  SPHENOIDALIS 


in  its  lateral  wall.  Indeed,  when  the  cavernous  sinus  is  elongated  dorsally 
the  mandibular  nerve  may  be  in  like  relations.  These  nerves,  save  the 
abducens,  lie  in  order  from  above  downward  and  backward. 

The  abducens  nerve  in  the  region  of  the  sphenoidal  sinus  is  com- 
monly located  lateral  to  the  internal  carotid  artery.  The  exact  relationship 
depends  upon  the  size  and  conformation  of  the  sphenoidal  sinus  and  the 
course  of  the  internal  carotid  through  the  cavernous  sinus.  Not  infre- 
quently, indeed,  the  abducens  nerve  is  located  lateral  to  the  internal  carotid 
artery  where  the  latter  immerges  into  the  cavernous  sinus,  then  courses 


N.  opticus k 

Cc .etkmvidcdcs  post.  \ 


a.  orbitai^  superior 
confajjwd  structures 


Ostium  sphcrwidufa  ] 
Conflux.  7/asaJ,is  inftrwr 


Sin,ir,s  max  JJarls 


FIG.    141.  —  A  coronal  or  frontal  section  through  the  head  of  an  adult.      Note  the  posterior  ethmoidal 
cells  extending  into  the  sphenoid  bone  and  encroaching  upon  the  sphenoidal  sinuses. 

caudal  to  and  parallels  the  artery  for  a  greater  or  less  distance,  and  finally 
again  passes  lateral  to  the  artery  as  the  latter  assumes  a  final  vertical 
course  and  the  nerve  emerges  from  the  cavernous  sinus  into  the  orbit. 
The  abducens  nerve  is,  therefore,  in  very  many  instances  in  direct  contact 
with  the  lateral  wall  of  the  sphenoidal  sinus  for  a  goodly  portion  of  its 
course  —  dura  mater  and  very  thin  bone  intervening  between  the  nerve 
and  the  mucous  membrane  of  the  sinus  (Fig.  199).  If  osseous  dehiscences 
exist  in  these  cases  the  mucous  membrane  alone  serves  as  a  barrier  between 
the  abducens  nerve  and  the  outside  air  or  any  secretions  that  may  be 
contained  in  the  sinus.  Moreover,  when  the  sphenoidal  sinus  expands 


CAVERNOUS  SINUS 


195 


into  the  ventral  portion  of  the  root  of  the  great  wing  of  the  sphenoid 
bone,  there  is  a  corresponding  encroachment  upon  the  superior  orbital 
(sphenoidal)  fissure  with  again  a  sinus  contact  for  the  abducens  nerve 
as  the  latter  emerges  from  the  cranial  cavity  through  the  superior  orbital 
fissure  into  the  orbit  (Fig.  139).  Again,  the  abducens  nerve  may  come 


FIG.  142. — A  dissection  of  the  cavernous  sinuses  and  related  parts.  On  the  right  side  the  plane 
of  section  is  oblique,  while  on  the  left  side  the  plane  of  section  is  purely  frontal.  Particularly  note 
the  extension  of  the  sphenoidal  sinus  of  the  right  side  beneath  the  cavernous  sinus.  It  is  in  these 
cases  that  the  Gasserian  ganglion  a,nd  the  mandibular  nerve  come  into  relationship  with  the  sphe- 
noidal sinus;  moreover,  that  direct  relations  with  the  temporal  lobe  of  the  brain  are  established. 

in  contact  with  the  sphenoidal  sinus  dorsal  to  the  internal  carotid  artery 
when  the  sinus  pneumatizes  or  extends  into  the  sloping  surface  of  the 
body  of  the  sphenoid  bone  dorsal  to  the  hypophyseal  fossa  (clivus  blumen- 


196  THE  SINUS  SPHENOIDALIS 

bachii,  Blumenbach's  slope).  Indeed,  the  oculomotor  nerve  likewise  may 
be  encroached  upon  in  the  latter  extension  of  the  sphenoidal  sinus. 

The  internal  carotid  artery  in  its  third  or  intracranial  course  ascends 
from  the  position  of  the  foramen  lacerum  medium,  where  it  escapes  from 
the  carotid  canal,  in  the  direction  of  the  posterior  clinoid  process,  soon, 
however,  to  bend  forward  and  immerge  into  the  dural  cavernous  sinus. 
It  courses  forward  in  the  dural  sinus  accompanied  by  the  abducens  nerve 
on  its  lateral  and  caudal  sides  (see  above),  to  again  bend  sharply  upward 
at  the  level  of  the  anterior  clinoid  process  and  emerge  from  the  cavernous 
sinus  by  piercing  its  wall,  i.e.,  the  dura  mater. 

In  the  vast  majority  of  cases  the  internal  carotid  artery  as  it  traverses 
the  dural  cavernous  sinus  pushes  the  lateral  wall  of  the  sphenoidal  sinus 
into  a  conspicuous  serpentine-like  mound  (Figs.  195  and  197).  The  promi- 
nence of  the  arterial  relief  is,  of  course,  largely  dependent  upon  the  degree 
of  lateral  expansion  of  the  sphenoidal  sinus.  However,  not  infrequently 
in  relatively  small  sinuses  is  the  relationship  very  intimate.  The  osseous 
wall  intervening  between  the  sinus  mucous  membrane  and  the  dura  mater 
and  the  internal  carotid  artery  is  very  commonly  of  extreme  delicacy. 
Indeed,  congenital  dehiscences  or  bony  defects  over  the  artery  are  of 
fairly  frequent  occurrence.  In  such  cases  the  thin  outer  dural  layer 
alone  intervenes  between  the  artery  and  the  sinus  mucosa  (Fig.  195). 
As  the  artery  emerges  from  the  cavernous  sinus,  it  courses  very  closely 
to  the  lateral  side  of  the  hypophyseal  fossa,  a  relationship  to  be  recalled 
in  hypophyseal  operations. 

The  almost  constant  and  extremely  intimate  relationships  of  the 
internal  carotid  artery  to  the  lateral  wall  of  the  sphenoidal  sinus  make 
operative  procedures  on  this  wall  of  the  sinus  exceptionally  hazardous. 
Moreover,  since  the  osseous  barrier  between  the  sinus  and  the  artery  is 
not  infrequently  deficient  or  at  best  but  of  a  papery  delicacy,  it  would 
appear  that  any  procedure  involving  cutting  or  curretting  to  be  unwar- 
ranted. In  addition,  the  very  common  irregularities  on  the  lateral  sphe- 
noidal wall  must  not  be  forgotten  as  well  as  other  structures  often  as  much 
exposed  as  the  internal  carotid  artery;  for  example,  the  abducens  nerve. 

In  conclusion  it  may  be  said  that  the  intimacy  of  the  relationships 
between  the  structures  contained  in  the  cavernous  sinus  and  the  sphenoidal 
sinus  is  dependent  upon  (i)  the  extent  of  the  cavernous  sinus  and  (2) 
the  degree  of  pneumatization  of  the  body  of  the  sphenoid  bone  and  the 
extensions  of  sphenoidal-sinus  recesses  and  diverticula  into  neighboring 
parts.  If  the  sphenoidal  sinus  extends  far  dorsolaterad,  the  semilunar 
ganglion  (Gasserian)  and  the  mandibular  nerve  may  be  intimately  related. 


DIMUNITIVE  SPHENOIDAL  SINUSES 


197 


If  the  root  of  the  lesser  wing  of  the  sphenoid  bone  is  partially  hollowed  out, 
the  optic  foramen  and  nerve  are  encroached  upon.  The  maxillary  nerve 
comes  into  intimate  relationship  with  the  sphenoidal  sinus  when  the  latter 
grows  in  the  direction  of  the  foramen  rotundum — a  very  common  condi- 
tion (Fig.  195).  Indeed,  the  maxillary  nerve  may  be  in  close  proximity 


Sitios  spkenaidaZis          Fossa.  Tiypopkyseos 


Cc.  ctkrrwidaJes*1 


FIG.  143.  —  A  sagittal  section  of  a  very  small  sphenoidal  sinus  from  an  adult.  The  intimate 
relations  that  usually  exist  between  the  sphenoidal  sinus  and  the  hypophysis  cerebri,  the  cavernous 
dural  sinus  and  the  related  structures  are  precluded  in  specimens  of  this  sort.  (Compare  with  Fig.  197.) 

to  the  sphenoidal  sinus  as  early  as  the  third  year.  The  sphenoidal  sinus 
very  commonly  encroaches  upon  the  confines  of  the  superior  orbital 
(sphenoidal)  fissure  and  because  of  this  establishes  intimate  topographical 


,  Fossa, 


Cc  et/imordaZes 


FIG.  144.  —  A  sagittal  section  of  the  body  of  the  sphenoid  bone,  etc.  Note  the  exceptionally 
small  sphenoidal  sinus  and  its  remote  relations  to  the  hypophyseal  fossa.  From  an  adult,  aged 
50  years. 

relationships  with  the  structures  that  are  transmitted  by  it,  et  cetera  (Fig. 


Diminutive  Sphenoidal  Sinuses.  —  Very  small  sphenoidal  sinuses  are 
now  and  then  encountered.     The  walls  are  proportionately  thick  and  pre- 


ig8 


THE  SINUS  SPHENOIDALIS 


elude  the  very  intimate  relations  between  the  sphenoidal  sinus  and  the 
neighboring  structures  previously  referred  to  (Figs.  143  and  144). 

Agenesis  of  the  Sphenoidal  Sinus. — Agenesis  of  the  sphenoidal  sinus 
is  very  uncommon  according  to  the  author's  observations.  Specimens 
were  observed  in  which  posterior  ethmoidal  cells-  pneumatized  the  body 


N.iiiaidlla  ris 
N.pptuus     i 


U  tide  fended 


or  7ton-ossev>s  area, 


NcancJis  jyter-yyoideus  (Victii)     \          \  J&obe  in  canaJ/is 
Gocnglion  splie*wpal^ijw,Tw(f{eGtelu)    \       (bone-  cut  oavay) 
Processes 


FIG.    145. — Paranasal  chambers  exposed  from  the  lateral  side.      Note  the  projection  of  a  posterior 
ethmoidal  cell  over  the  pterygopalatine  fossa. 

of  the  sphenoid  bone,  the  sphenoidal  sinuses  proper  being  represented  by 
mere  rudiments  on  the  ventrocaudal  wall  of  the  body  of  the  sphenoid  bone. 
Moreover,  a  few  cases  were  encountered  in  which  the  body  of  the  sphenoid 
bone  was  solid  and  wholly  unpneumatized,  save  for  very  slight  depressions 


CONCLUDING,     CONSIDERATIONS 


199 


in  wide  communication  with  the  sphenoethmoidal  recesses  on  the  ventral 
or  nasal  surface  of  the  sphenoidal  body. 

Concluding  Considerations. — It  is  well  known  that  little,  if  any,  in- 
formation of  value  regarding  the  size  of  the  sphenoidal  sinus  in  infancy  can 
be  obtained  from  the  skiagram.  The  solid  body  of  the  sphenoid  bone 
throws  too  dense  a  shadow  at  an  early  postnatal  period.  Haike,  however, 
differentiated  the  sphenoidal  sinus  in  the  skiagram  at  the  age  of  3! 


PIG.    146. — Photograph  of 


an  adult  bodv. 


years,  the  cavity  presenting  a  brighter  area  within  the  dark  shadow  of 
the  body  of  the  sphenoid.  Turner  and  Porter  throw  out  a  caution  in  the 
interpretation  of  skiagrams  of  the  sphenoidal  region  in  very  young  people. 
They  claim  that  one  may  be  deceived  by  the  lighter  shadow  presented  by 
the  cancellous  tissue  of  the  body  of  the  sphenoid  bone.  The  development 
and  size  of  the  sphenoidal  sinus  is  ascertained  to  the  best  advantage  by 
profile  views  of  the  head.  A  comparison  between  skiagrams  and  actual 
measurements  of  the  sphenoidal  sinus  during  the  childhood  period  as 
given  in  Table  I,  page  178,  is  helpful  in  arriving  at  the  size  and  shape  of 


200  THE   SINUS  SPHENOIDALIS 

the  cavity  at  a  given  period.  Haike  cautions  that  operators  must  always 
remain  conscious  of  the  limitations  of  the  skiagram,  yet  owing  to  the  diffi- 
culty of  endonasal  investigations  in  the  young  child  he  hopes  to  obtain 
conclusive  evidence  from  the  skiagram  alone.  However,  in  older  children 
he  believes  that  one  ought  always  to  be  guided  more  by  the  result  of  clin- 
ical examination  than  by  the  skiagram.  Onodi  likewise  holds  that  the 
clinical  signs  be  considered  principally  and  the  skiagram  be  used  only  as 
a  secondary  aid  to  diagnosis;  moreover,  believes  that  while  this  is  true  in 
general  in  connection  with  accessory  sinus  troubles,  it  is  particularly  ap- 
plicable to  diseases  of  the  sphenoidal  sinus  in  children.  The  sphenoidal 
sinus  has  been  successfully  treated  by  radical  operation  in  children  of  6 
years  of  age.  Onodi  believes  that  resection  of  the  sphenoidal  sinus  in 
the  first  years  of  childhood  should  be  performed  through  the  ethmoidal 
labyrinth. 

In  the  adult,  skiagraphy  of  the  sphenoidal  sinus  is  valuable  in  delineat- 
ing the  ventrodorsal  size  of  the  cavity  and  the  thickness  of  the  sinus  walls. 
Of  course,  a  profile  skiagram  is  desirable.  Moreover,  the  skiagram  is 
valuable  in  diseased  conditions,  as  a  means  of  diagnosis  and  assistance  in 
determining  the  anatomical  contour  and  size  of  the  sinus  in  a  particular 
case.  However,  it  is  well  known  that  the  skiagram  is  of  less  anatomical 
assistance  preliminary  to  operations  in  case  of  the  sphenoidal  sinus  than  it 
is  in  the  frontal  and  maxillary  sinuses.  This  is,  however,  not  true  in  the 
sphenoidal  approach  of  the  pituitary  body  surgically.  Roentgenography 
is  indispensable  in  the  establishment  of  the  indications  and  in  the  operation 
itself.  The  radiogram  clearly  outlines  the  size  of  the  hypophyseal  fossa 
and  its  exact  relation  to  the  sphenoidal  sinus.  Moreover,  it  gives  some 
evidence  of  the  size  of  the  sphenoidal  sinus  and  the  distance  from  the  ven- 
tral surface  of  the  sphenoid  bone  to  the  anterior  nasal  spine. 

Pfahler1  in  1916  described  a  new  method  of  study  of  the  paranasal 
or  accessory  sinuses  with  the  roentgen  rays.  He  employs  a  technic  where- 
by a  roentgen-ray  film  is  inserted  into  the  mouth  and  the  roentgen-ray  tube 
adjusted  over  the  head  so  that  the  rays  course  more  or  less  at  right  angles 
to  the  film.  The  method  appears  to  be  of  especial  advantage  when  skia- 
grams of  the  ethmoid  labyrinth  and  sphenoidal  sinuses  are  desired.  The 
several  paranasal  sinuses  appear  in  the  picture  in  isolated  positions  with 
less  overlapping  than  in  other  methods.  This  is,  of  course,  of  distinct 
advantage. 

In  disease  of  the  sphenoidal  sinus  it  is  well  to  recall  the  intimate 
anatomic  relations  to  important  structures.  Optic  neuritis,  even  blind- 

1  Laryngoscope,  July,  1916. 


COXCLUDIXG  CONSIDERATIONS  201 

ness,  may  ensue.  Infection  of  the  sphenoidal  sinus  and  the  ophthalmic 
vein  may  lead  to  cavernous  sinus  thrombosis.  Certain  of  the  cranial 
nerves  related  to  the  cavernous  sinus  may  be  paralyzed.  Ventrally  the 
cavernous  sinus  receives  as  tributaries  the  ophthalmic  vein  and  farther 
dorsad,  occasionally,  the  basilar  vein  and  veins  from  the  related  dura 
mater.  Moreover,  the  two  sinuses  are  interconnected.  The  blood  is 
carried  from  the  cavernous  sinus  by  the  two  petrosal  dural  sinuses  and  by 
veins  which  leave  its  caudal  surface  to  pass  extracranially  through  the 
foramina  in  the  sphenoid  bone,  etc.  It  is  well  known  that  the  cavernous 
sinus  may  become  infected  from  sources  other  than  the  sphenoidal  sinus, 
e.g.,  from  foci  far  removed,  especially  through  the  extraorbital  anasto- 
moses of  the  ophthalmic  veins.  The  anatomy  is  such  that  cavernous 
sinus  infection  and  thrombosis  may  follow  ulceration  of  the  nasal  mucosa, 
alveolo-dental  periostitis,  empyema  of  other  paranasal  sinuses,  infections 
of  the  face,  infections  of  diploic  tissue  in  the  region  of  the  forehead.  Natu- 
rally, therefore,  in  obstruction  to  the  blood  flow  through  the  cavernous 
sinus,  as  in  thrombosis,  there  would  be  edema  of  the  eyelids  and  side  of  the 
nose  and  upper  face,  and  an  exophthalmos ;  and  if  the  structures  that  are 
related  to  or  contained  within  the  cavernous  sinus  should  be  involved, 
there  would  be  ptosis,  pupil  irregularities,  strabismus,  pain,  etc. 

In  curretting  or  cleaning  pathological  tissue  from  the  sphenoidal 
sinuses,  due  regard  must  be  had  for  the  very  important  structures  im- 
mediately ectal  to  the  thin-walled  sinus.  In  extensive  pneumatization 
many  or  all  of  the  structures  mentioned  may  have  the  most  intimate 
anatomic  relations  to  the  sinuses.  Particularly  would  the  author  call 
attention  to  the  cavernous  sinus  and  internal  carotid  artery  as  structures 
readily  injured,  especially  so  in  those  cases  where  the  osseous  wall  is 
deficient  and  the  inner  wall  of  the  cavernous  sinus  in  direct  contact  with 
the  mucosa  of  the  sphenoidal  sinus.  In  case  of  the  internal  carotid  artery 
the  outer  (ectal)  dural  layer  alone  would  intervene  between  the  vessel 
and  the  sinus  mucosa.  This  is  also  frequently  true  for  a  short  segment 
of  the  abducens  nerve  (page  194  and  Fig.  197). 

The  Vidian  nerve  in  the  floor,  the  maxillary  nerve  as  it  traverses  the 
foramen  rotundum,  and  the  optic  nerve  in  its  course  through  the  optic 
foramen  are  the  most  constant  nerves  in  intimate  relationship  with  the 
sphenoidal  sinus. 

The  auditive  tube  (tuba  auditiva  Eustachii)  is  as  a  rule  too  far  re- 
moved from  the  sphenoidal  sinus  to  become  involved  in  sinus  disorders 
unless  the  sphenoidal  sinus  extends  its  pneumatization  extensively  into 
the  pterygoid  process  in  the  formation  of  the  pterygoid  recess  (Fig.  139). 


202  THE   SINUS  SPHENOIDALIS 

The  latter  may  establish  intimate  anatomic  relationships  with  the  auditive 
tube  and  be  a  factor  in  infecting  the  mucous  membrane  of  the  tube,  since 
the  recess  is  so  dependent  and  far  removed  from  the  aperture  of  the 
sphenoidal  sinus  that  infectious  materials  are  readily  retained  within  its 
confines.  The  auditive  or  Eustachian  tube  extends,  of  course,  between 
the  nasopharynx  and  the  tympanic  cavity  or  middle  ear.  Moreover,  the 
pharyngeal  ostium  of  the  auditive  tube  is  always  in  juxtaposition  to  the 
dorsal  extremity  of  the  inferior  nasal  meatus  and  is,  therefore,  readily 
involved  secondarily  in  certain  disorders  of  the  nasal  fossa,  since  the  mu- 
cous membrane  is  directly  continued  from  the  nasal  fossa  into  the 
nasopharynx  and  from  there  into  the  auditive  tube. 


VI-THE  ETHMOIDAL  CELLS 


CHAPTER  VI 


THE  ETHMOIDAL   CELLS 
THE  FETAL   STAGE 

The  ethmoidal  air  cells  (cellulae  ethmoidales)  are  primarily  extensions 
or  e vagina tions  of  the  nasal  mucosa  from  the  middle,  superior,  and  first 
supreme  nasal  meatuses;  e.g.,  from  the  meatuses  directly  or  from  the  acces- 
sory furrows  and  recesses  which  configure  their  lateral  walls,  particularly 
the  lateral  walls  of  the  middle  and  superior  meatuses.  The  reader  is  re- 
ferred to  previous  paragraphs  concerning  the  early  anatomy  of  the  major 


FronfaJ  folds 

Heccssuj  f rot  it  ah' s 


'"-;-  frontal  fyrroas 


^•*  Concha  nas.med. 

FIG.  147.  FIG.  148. 

FIGS.   147-148. — Frontal  sections  through  the  frontal  recess  of  a  7-month  fetus.     Section  Fig.  147. 

is  farther  ventral  than  is  section  Fig.  148. 

Note  the  blind  ventral  extremities  of  the  frontal  furrows  in  section  Fig.  147.  Strictly  speaking 
these  are  early  cellule  ethmoidales  anterior.  In  section  Fig.  148,  some  of  the  furrows  or  cells  are 
shown  to  be  in  free  communication  with  the  frontal  recess.  Any  one  of  these  cells  may  develop  suffi- 
ciently far  to  become  the  frontal  sinus.  Indeed,  we  see  here  the  potentials  for  multiple  frontal 
sinuses.  The  frontal  recess  proper  also  frequently  gives  rise  to  the  frontal  sinus.  X  10.  (After 
J.  P.  S.) 

meatuses  and  the  accessory  or  secondary  furrows  and  the  major  and 
secondary  conchas  since  they  play  such  an  important  role  in  determining 
the  location  of  the  initial  ethmoidal  cells. 

The  initial  ethmoidal  out-pouchings  are  in  evidence  as  early  as  the 

205 


206 


THE  ETHMOIDAL  CELLS 


fourth  month  of  fetal  life.  For  some  time  the  surfaces  of  the  mucous- 
membrane  sacs  are  in  many  cases  in  contact  and  the  lumina  in  a  sense 
merely  potential,  again  the  early  sacs  may  be  mere  dimple-like  depressions. 
However,  by  the  seventh  month  the  evaginations  have  taken  sl^ape  in 
the  form  of  hollow  tubular-like,  blindly  ending  sacs,  with  ostia  in  communi- 
cation with  the  points  of  initial  outgrowth.  These  tubular  sacs  may 
now  truly  said  to  be  ethmoidal  cells.  Horizontal  sections  of  the  nose  of 


frontal      , 

farrows 

(cc.  eth.  ant.) 


'furrows 


Frontal  folds  or 
accessory  cone-fiat 

4 

^_v  five,  uncittafus 
(ace.  concha ) 


XT- 

•^f         Infundf.0.  etk. 


~-j-f 


FIG.   149.  FIG.   150. 

FIGS.  149-150. — Drawings  of  frontal  sections  through  the  left  nasal  fossa  in  the  region  of  the 
frontal  recess.  Note  the  early  frontal  furrows,  rudiments  of  anterior  ethmoidal  cells.  Fig.  149, 
from  a  term  fetus,  series  D,  slide  4;  Fig.  150,  from  a  7-month  fetus,  series  B,  slide  31. 

the  term  fetus  show  the  ethmoidal  cells  considerably  developed,  the 
anterior  group  measuring  on  the  average  5X2X3  mm.  and  the  posterior 
group  5X4X2  mm.  Reconstruction  of  the  "term"  ethmoidal 
labyrinth  is  a  valuable  method  of  study  of  the  early  stages. 

THE  CHILDHOOD  STAGE 

The  lateral  masses  of  the  ethmoid  bone  and  its  appendages  (the  major 
and  accessory  conchae)  are  primitively  solid  structures.     Soon,  however, 


CHILDHOOD  STAGE  207 

the  lateral  masses  become  more  or  less  honeycombed  or  labyrinth-like 
by  the  developing  ethmoidal  celts.  In  the  formation  of  the  ethmoidal 
labyrinth  there  is  no  uniformity  of  development.  In  a  general  way  the 
anterior  group  of  the  ethmoidal  cells  develop  ventral  to  the  posterior 
group.  There  is,  however,  at  times  considerable  overlapping  of  the  two 
groups.  Each  cell  as  it  grows  from  a  preformed  furrow  or  recess  tends 
more  or  less  toward  the  cribriform  plate  of  the  ethmoid  bone.  Even 
though  a  certain  cell  has  its  anlage-point  farther  inferior  than  another 
cell,  it  may  outgrow  its  neighbor  and  force  the  latter  to  progress  in  a  direc- 
tion other  than  toward  which  it  was  primarily  directed,  indeed,  dwarf 
its  growth.  Later  the  cells  in  honeycombing  the  lateral  ethmoidal 
masses  grow  in  almost  any  direction.  Cells  that  arise  from  unlike  me- 
atuses,  never  communicate  with  each  other.  Furthermore,  a  cell  always 
communicates  with  the  meatus  from  which  it  develops. 

There  is  early  a  division  topographically  of  the  ethmoidal  field  into 
two  groups:  (i)  cellula  ethmoidales  anterior,  (2)  cellulce  ethmoidales  pos- 
terior. The  anterior  group  develop  from  points  caudal  (inferior)  to  the 
attached  border  of  the  middle  nasal  concha  and  the  posterior  group  from 
points  cephalic  (superior)  to  the  attached  border  of  the  middle  nasal  con- 
cha. The  so-called  cellules  ethmoidales  media  (middle  group)  are  here 
classed  with  the  anterior  group.  This  is  a  better  classification  since  the 
cells  which  grow  from  the  accessory  furrows  of  the  descending  ramus  of  the 
middle  nasal  meatus  (bullar  furrows  and  infundibulum  ethmoidale)  are 
closely  associated  with  the  cells  (the  old  anterior  group)  which  grow  from 
the  ascending  ramus  (frontal  recess  and  its  furrows)  of  the  middle  nasal 
meatus  and  from  the  ventral  and  cephalic  extremity  of  the  infundibulum 
ethmoidale. 

As  stated  previously,  the  frontal  furrows  on  the  lateral  wall  of  the 
frontal  recess  vary  in  number.  There  may,  indeed,  be  a  total  absence 
(Fig.  40) ;  the  frontal  recess  then  appearing  as  a  simple,  blind  outgrowth 
from  the  meatus  medius.  The  furrows  and  recess  develop  variously  into 
anterior  ethmoidal  cells,  and,  in  addition,  the  frontal  sinus  in  the  majority 
of  cases  develops  as  an  outgrowth  from  this  region.  Some  of  the  furrows 
remain  extremely  shallow  and  never  reach  the  dignity  of  ethmoidal  cells. 
Indeed,  regression  is  operative  in  some  instances  and  some  furrows  may 
disappear  altogether,  either  by  a  coalescence  of  bordering  folds  or  other- 
wise. The  agger  nasi  is  very  commonly  pneumatized  by  the  most  ventral 
of  the  ethmoidal  cells  developing  from  the  frontal  furrows. 

The  infundibulum  ethmoidale  may  terminate  ventrally  and  superiorly 
by  dilating  into  a  single  ethmoidal  cell  lateral  to  the  frontal  recess  and  its 


208 


TIIK   KTIIMOIDAL  CKLLS 


derivatives.  However,  it  is  not  uncommon  to  find  from  two  to  four  cells 
growing  out  from  its  ventral  extremity.  These  infundibular  cells  have 
varied  relationships.  Some  may  grow  sufficiently  far  into  the  frontal  bone 
to  become  frontal  sinuses.  Others  may  impinge  upon  the  frontal  sinus 
and  produce  bullar-like  swellings  on  the  sinus  floor.  Again,  they  grow 
into  the  agger  nasi,  the  processus  uncinatus,  etc. 

The  bullar  cells  (the  former  middle  ethmoidal  cells)  vary  in  number 
from  one  large  cell  to  five  or  more  smaller  ones.  In  fully  95  per  cent,  of 
cases  cells  arise  as  extensions  from  the  preformed  suprabullar  furrow  and 


PIG.    151. — The  paranasal   sinuses  in  a  child  aged  16  months.      The  nasal  wall  of  the  maxillary  sinus 

has  been  removed.      Reduced. 

Rf  =  recessus  frontalis;  SI  =  saccus  lacrimalis;  le  =  infundibulum  ethmoidale;  Dnl  =  ductus 
nasolacrimalis;  Sm  =  sinus  maxillaris;  Si  =  sinus  sphenoidalis;  He  =  hypophysis  cerebri;  Tp  = 
tonsilla  pharyngea;  Ota  =  ostium  tuba  auditiva. 

in  12  per  cent,  of  cases  from  the  infrabullar  furrow.  Occasionally  (8 
per  cent.)  the  bullar  furrow  gives  rise  to  an  ethmoidal  cell.  These  cells 
early  hollow  out  the  accessory  concha  (bulla  ethmoidalis)  and  frequently 
extend  into  the  supraorbital  plate  of  the  frontal  bone  and  into  the  infra- 
orbital  plate  of  the  maxilla.  Their  size  greatly  influences  the  width  of 
the  infundibulum  ethmoidale  and  the  hiatus  semilunaris,  and  incidentally 
the  natural  drainage  channels  of  the  maxillary  sinus. 

During  childhood  the  posterior  ethmoidal  cells  gradually  pneumatize 
and  make  shell-like  the  superior  and  supreme  conchse.  Even  before 
puberty  the  cells  may  extend  into  the  supraorbital  plate  of  the  frontal 


CHILDHOOD  STAGE 


209 


bone  and  into  the  infraorbital  plate  of  the  maxilla.  Indeed,  the  author 
has  seen  as  early  as  the  tenth  year  marked  extensions  into  the  body  of  the 
sphenoid  bone  and  into  the  maxilla,  the  latter  simulating  a  duplicated 
maxillary  sinus.  Such  ethmoidal-cell  extensions,  however,  never  normally 
communicate  with  either  the  sphenoidal  or  maxillary  sinuses.  Even 
before  birth  one  frequently  sees  extensions  into  the  middle  nasal  conchae. 
Growth  of  a  posterior  ethmoidal  cell  into  the  orbital  process  of  the  palate 
bone  is,  likewise,  encountered  (palatal  sinus). 


PIG.  152. — A  photograph  of  a  dissection  of  the  paranasal  sinuses  of  a  child  aged  8  years,  2  months 
and  10  days.  The  inset  in  the  lower  right-hand  corner  illustrates  the  sphenoidal  sinus  and  its  rela- 
tion to  the  hypophysis  cerebri.  (Dissection  by  Dr.  Warren  B.  Davis.) 

It  is  well  to  remember  that,  owing  to  the  relatively  narrow  nasal  fossa, 
it  is  difficult  to  explore  the  ethmoidal  field  by  the  endonasal  route  in  the 
young  child.  However,  it  must  not  be  forgotten  that  even  in  early 
childhood  both  the  anterior  and  posterior  groups  of  ethmoidal  cells  are 
fairly  well  established  and  subject  to  diseases.  Surgeons  have  radically 
operated  upon  the  ethmoidal  cells  in  the  child  through  the  maxillary 
sinus  and  by  way  of  the  frontal  sinus.  Meyer  operated  upon  the  eth- 
moidal labyrinth  by  way  of  the  maxillary  sinus  in  a  child  between  3  and 


210  THE  ETHMOIDAL  CELLS 

4  years  of  age.  The  skiagram  is  a  valuable  aid  in  the  delineation  of  the 
ethmoidal  field  in  the  child,  but  its  limitations  must  be  kept  in  mind. 
The  early  frontal  sinus  may  readily  be  confused  with  the  ethmoidal  cells. 
Haike,  according  to  Onodi,  believes  "that  a  reliable  diagnosis  of  ethmoidal 
affections  in  children  can  only  be  obtained  by  skiagraphy."  However, 
he  throws  out  the  following  caution  :  "  In  young  children  the  picture  of  the 
ethmoidal  cells  in  the  skiagram  is  so  narrow  that  it  is  sometimes  difficult 


Jf.opticns 
A,carotis  intcrita      \  Bulla,  ethmoidalis          / 


TonsillM. phcayngea,  •       Concha,  iiasalis 

C.pterygoid(ius(Vidii) 

J*roc. 


PIG.  153. — A  dissection  of  the  paranasal  sinuses  and  the  nasolacrimal  duct  of  a  male  child  aged 
1 1  years.  Note  that  the  degree  of  pneumatization  and  the  relation  of  the  several  paranasal  chambers 
are  essentially  those  of  the  adult.  The  Vidian  nerve  is  intimately  related  to  the  floor  of  the  sphe- 
noidal  sinus.  The  arrow  in  the  middle  nasal  meatus  indicates  an  accessory  maxillary  ostium. 

to  arrive  at  a  definite  diagnosis;  thus,  even  moderate  congestion  of  the 
mucous  membrane  may  veil  the  lumina  of  the  small  ethmoidal  cells. 
With  regard  to  the  question  whether  the  anterior  or  posterior  ethmoidal 
cells  are  affected,  the  skiagram  can  give  no  more  information  in  children 
than  in  the  adult." 

Table  L  gives  the  size  of  the  ethmoidal  cells  of  the  childhood  period 
of  a  series  measured  by  the  author.     Great  variation  is,  of  course,  en- 


ADULT  STAGE 


countered  and  is  to  be  expected  among  the  several  cells  composing  the 
ethmoidal  labyrinth.  The  great  discrepancy  in  the  size  of  the  cells  at  a 
given  age  is  largely  due  to  the  great  variability  in  the  number  of  cells 
differentiated.  The  fewer  the  cells  the  larger  will  be  the  several  measure- 
ments, since  the  ethmoidal  labyrinth  will  occupy  the  entire  ethmoidal 
field  whether  composed  of  few  or  many  cells.  The  author  found  the 
number  of  cells  to  vary  from  three  to  fifteen. 

TABLE  L 


Cephalocaudal, 
Age                                Group                               mm. 
(height) 

Mediolateral, 
mm. 
(width) 

Ventrodorsal, 
mm. 
(length) 

Newborn 

Anterior 
Posterior 

5                                    2 

5                                    4 

2 
2 

Anterior 

2-8                              1.5-6 

2-7 

i  year 

Posterior 

2-8 

1-5-7 

2-9 

.       Anterior 

3-9 

2-6 

2-6 

2  years 

Posterior 

5-8 

3-4 

4-6 

Anterior 

7-8 

5-7 

5-6 

5  years 

Posterior 

7-8 

7-10 

6-7 

Anterior                       8-n 

7-10 

6-7 

8  years 

Posterior                     8-n 

7-10 

9-16 

Anterior                      9-12 

8-12 

8-10 

10  years 

Posterior                     9-14 

8-12 

0-17 

Anterior                      9-16 

IO 

5-23 

14  years 

Posterior 

9-15 

14                            8-20 

THE  ADULT  STAGE 

General  Considerations. — The  great  complexity  of  the  adult  eth- 
moidal labyrinth  and  the  variations  in  size,  shape  and  disposition  of  the 
individual  cells  composing  it  are  in  accord  with  the  early  anatomy  and 
potentialities  of  development. 

The  fully  developed  ethmoidal  labyrinth  occupies  the  field  between 
the  medial  surfaces  of  the  bony  orbits  and,  generally  speaking,  extends 
between  the  frontal  sinuses  ventrally  and  the  sphenoidal  sinuses  dorsally. 
Cephalically  (above)  the  cribriform  laminae  serve  as  the  boundary  planes, 
while  the  uncinate  processes  represent  the  caudal  limit  of  the  labyrinth. 
One  must,  however,  bear  in  mind  that  almost  constantly  the  ethmoidal 
labyrinth  extends  beyond  one  or  more  of  the  true  boundaries  of  the  eth- 
moidal field  in  the  formation  of  ethmofrontal,  ethmolacrimal,  ethmomaxil- 
lary,  ethmosphenoidal  and  ethmopalatine  cells.  Moreover,  not  infre- 
quently, cellular  extensions  into  the  overhanging  middle  nasal  concha 
(cellulae  conchales)  extend  the  ethmoidal  labyrinth  below  the  level  of  the 
uncinate  process. 


212  THE  ETHMOIDAL  CELLS 

The  mesethmoid  (lamina  perpendicularis)  divides  the  ethmoidal 
labyrinth  into  two  more  or  less  symmetrical  and  independent  lateral 
halves.  However,  at  times  one  or  the  other  half  is  markedly  enlarged 
at  the  expense  of  its  fellow. 

Classification. — The  embryology  and  adult  anatomy  of  the  ethmoidal 
cells  justify  the  classification  appended  in  Table  M. 

As  stated  elsewhere  the  adult  ethmoidal  cells  are  seldom  wholly  con- 
fined within  the  ethmoid  bone.  Their  osseous  boundaries  are  variously 
completed  by  the  articulation  of  the  ethmoid  with  neighboring  bones, 
e.g.,  the  frontal,  lacrimal,  sphenoid,  palate,  and  maxilla.  While  in  many 
cases  related  bones  merely  serve  to  complete  the  osseous  outlines  of  eth- 
moidal cells  at  the  planes  of  articulation,  they  not  infrequently  lodge 
extensive  cellular  outgrowths  from  the  ethmoidal  labyrinth.  These  ex- 
tensions are  particularly  common  into  the  supraorbital  plate  of  the  frontal 
bone  and  into  the  infraorbital  plate  of  the  maxilla.  Moreover,  the  ex- 
tension of  posterior  ethmoidal  cells  into  the  bodies  of  the  sphenoid  and 
maxillary  bones,  there  encroaching  upon  the  sphenoidal  and  maxillary 
sinuses  respectively,  must  always  be  kept  in  mind  when  dealing  with  these 
sinuses.  Indeed,  the  maxillary  extension  is  often  mistaken  for  a  super- 
numerary maxillary  sinus  (see  page  119  and  Fig.  101).  Extensions  into 
the  lacrimal  and  palate  bones  are  frequent,  but  of  less  practical  importance. 
The  extension  into  the  palate  bone  is  often  referred  to  as  the  palatal 
sinus.  This  is  to  be  regretted  because  it  implies  an  individual  sinus  when 
in  reality  it  is  nothing  other  than  a  part  of  the  ethmoidal  labyrinth. 

Very  commonly  the  anterior  group  of  ethmoidal  cells  encroach  upon 
the  frontal  sinus,  even  extend  into  the  frontal  bone  to  become  topograph- 
ically frontal  sinuses  (Fig.  118).  Such  cells  frequently  produce  bullous- 
like  elevations  on  the  floor  of  the  frontal  sinus.  They  are  frequently 
referred  to  as  frontal  bullae  (bullae  frontales).  Furthermore,  cells  of  the 
ventral  group  not  infrequently  grow  into  the  middle  nasal  concha,  the 
agger  nasi,  and  the  uncinate  process. 

It  is  impossible  in  very  many  instances  to  judge  whether  a  cell  be- 
longs to  the  anterior  or  the  posterior  ethmoidal  group  merely  from  its 
position.  It  is  the  location  of  the  ostium  rather  than  the  body  of  the  cell 
that  determines  its  classification;  the  anterior  group  draining  into  the 
middle  nasal  meatus  and  the  posterior  group  into  the  superior  and  first 
supreme  meatuses. 

Dehiscences. — The  osseous  boundaries  of  the  ethmoidal  cells  are  not 
infrequently  defective ;  particularly  are  dehiscences  common  in  the  orbital 
plate  (os  planum,  lamina  papyracea)  of  the  ethmoid  bone.  The  author 


CLASSIFICATION 
TABLE  M. — CELLULE  ETHMOIDALES 


213 


Primary  groups 

Secondary 
groups 

Genetic  areas 

Communication  in  adult 

Cellula;  ethmoid- 
ales  anterior 

3 
I 

C 
I 

i 

a 

0 

Cellulae  fron-  (fl)  Frontal  recess 
tales               (b)  Frontal  furrows 

Frontal  recess  of  meatus  nasi 
medius 

Meatus  nasi  medius 

Cellulae    in-  .  Infundibulum  ethmoidale 
fundibu- 
lares 

Infundibulum  ethmoidale 

Cellulae  bul- 
ls 

Bullar    furrows,    especially 
the    suprabullar    and    the 
infrabullar 

Suprabullar  furrow 

Infrabullar  furrow 

Bullar  furrow 

(a)  Meatus  nasi  medius 

Meatus    nasi     medius     (di- 
rectly) 

Cellulae  con-    (b)  Infundibulum  ethmoidale 
chales 

Infundibulum  ethmoidale. 

(c)  Merely  extensions  of  other 
anterior  ethmoidal  cells 

Other     anterior     ethmoidal 
cells 

Cellular  ethmoid- 
ales  posterior 

Of  meatus  nasi  superior 

Cellulae  su- 
perior 

(a)  Ventral  extremity  of  the 
meatus  nasi  superior 

Meatus  nasi  superior 

(b)  Recessus  superior  of  me- 
atus nasi  superior 

(c)  Recessus   inferior  of   the 
meatus  nasi  superior 

Cellulae  con- 
chales 

(a)  Ventral  extremity  of  the 
meatus  nasi  superior 

Meatus    nasi    superior    (di- 
rectly) 

(b)  Recessus  inferior  of  the 
meatus  nasi  superior 

(c)  Merely  extensions  of  other 
posterior  ethmoidal  cells 

Other    posterior    ethmoidal 
cells. 

Cellulae  su- 
premae  I  (of 
meatus  nasi 
supremus  I) 

Meatus  nasi  supremus  I 

Meatus  nasi  supremus  I 

Extraethmoidal    Extensions    of  Cellulae    Ethmoidales:    (a)    Ethmofrontal,    (b)   Ethmo- 
lacrimal,  (c)  Ethmomaxillary,  (d)  Ethmosphenoidal,  (e)  Ethmopalatine 


214 


THK   KTHMOIDAL  CKLLS 


has  likewise  observed  a  number  of  specimens  in  which  the  mucous  mem- 
brane of  ethmoidal  cells  was  in  actual  contact  with  the  dura  mater.  The 
importance  of  these  dehiscences  in  the  spread  of  infection  from  the  eth- 
moidal labyrinth  to  the  tissues  of  the  orbit  and  the  meninges  must  ever 
be  kept  in  mind  by  the  clinician.  Moreover,  it  is  extremely  common  to 
find  that  the  osseous  wall  between  certain  of  the  anterior  ethmoidal  cells 
and  the  lacrimal  fossa  is  congenitally  deficient,  whereby  the  mucous  mem- 
brane of  the  cells  comes  into  actual  contact  with  the  lacrimal  sac.  It 
seems  certain  from  the  anatomy  of  the  region  that  the  nasolacrimal  pas- 
sageways must  commonly  suffer  infection  by  a  direct  extension  from  the 
ventral  ethmoidal  labyrinth  (see  page  255). 

Size  of  the  Ethmoidal  Labyrinth.— The  accompanying  Table  N 
gives  the  size  of  the  adult  ethmoidal  labyrinth  and  its  subgroups  as 
determined  by  several  measurements  of  a  number  of  specimens  selected 
at  random  from  a  larger  series.  The  discrepancy  in  the  ventrodorsal 

TABLE  N. — THE  ADULT  ETHMOIDAL  LABYRINTH 
(All  measurements  are  in  millimeters) 


Cellulae  anterior 


Cellulae  posterior 


Labyrinth 


Number      Side 

Cephalo- 
caudal 

Ventro- 
dorsal 

Medio- 
lateral 

Cephalo- 
caudal 

Ventro- 
dorsal 

Medio- 
lateral 

Cephalo- 
caudal 

Ventro-      Medio- 
dorsal        lateral 

I 

r     R    38 

25      13      35      26     12      40      34 

15 

I    \     T 

(   L      40 

14     12      38      23 

13         41        32 

13 

/ 

R      19 

10 

6 

16 

18 

II 

17      27 

ii 

2   I 

L      15 

ii 

10 

17 

16 

10 

17 

20 

10 

/ 

R     18 

14 

8      23      26     10 

30      36 

12 

3   I 

L      34 

25 

16      30      25     15 

35      35 

16 

r  R 

22 

7 

20 

28     28 

20      36 

13 

4  l 

L      16 

22 

9 

16 

20        10 

20      36 

13 

5   (   R     I? 

38 

10 

6 

12 

8 

19      40 

IO 

1   L      17 

32 

10 

12 

15 

8 

19 

32 

12 

/   R     30 

20 

18 

25 

23        12 

36 

34 

18 

I   L      31 

20 

18 

25 

20        23 

36 

30 

18 

7< 

R     18 

14 

7 

23 

25 

10 

30 

34 

IO 

1 

L      34 

26 

15 

31 

25 

13 

30     32 

15 

r 

R     17 

38 

9 

7      12 

7 

20        48 

17 

\l  L      15 

31 

10 

10  , 

15 

8 

20 

17 

17 

Average      23  .  6 

22.6 

ii.  i    20.  8    20.  5    12.3 

26.8      32.7 

14- 

ANTERIOR  ETHMOIDAL  CELLS 


215 


diameter  of  the  whole  ethmoidal  labyrinth  as  compared  with  the  combined 
diameters  of  the  anterior  and  posterior  groups  of  cells,  is  due  to  the  fact 
that  there  is  considerable  variation  at  the  junction  point  of  the  two  groups, 
particularly  in  the  degree  of  overlapping.  Usually  the  combined  ventro- 
dorsal  diameters  of  the  anterior  and  posterior  ethmoidal  groups  exceed 

Foramen  ethmaidodc  <nit.  fbrcunfin,  ethnwidsjJa  post. 

Orbitcc (         I       ',    fom&n&w*  spfanxjpMjdafoijn. 

Cc  .ct/i,7?zvfda2&s        \        \       \        \  SMU^S  sp/wmsulctiis 
\       \        ;  \Fhssa.  fiypophyseos 

•&^j 

*y 


i — 

FIG.    154. — A  dissection  of  the  paranasal  sinuses  exposed  from  the  lateral  aspect. 

the  ventrodorsal  diameter  of  the  ethmoidal  labyrinth  measured  as  a  whole. 
The  difference  between  the  measurements  of  the  right  and  left  sides  is 
insignificant  according  to  this  series.  Now  and  then  isolated  cases,  how- 
ever, show  a  marked  difference. 

The    Anterior    Ethmoidal   Cells    (cellulae   ethmoidal es  anterior).— 
The  anterior  ethmoidal   cells  vary  in  number  from  two  to  eight  in  the 


2l6  THE  ETHMOIDAL  CELLS 

series  of  specimens  studied.  They  invariably  communicate  by  individual 
ostia  with  some  portion  of  the  middle  nasal  meatus  under  cover  of  the 
middle  concha.  The  size  of  the  individual  cells  is  in  a  large  measure 
dependent  upon  the  number  of  cells  that  are  differentiated  in  a  particular 
case,  the  fewer  the  number  the  larger  the  cells,  and  vice  versa  (Figs.  127 
and  140). 

Genetically  the  anterior  group  of  ethmoidal  cells  is  clearly  divided 
into  three  main  subgroups.  In  the  adult,  however,  the  position  of  the 
individual  cells  is  often  misleading  if  one  would  judge  the  classification 
from  the  position  of  the  cell  alone.  It  is,  therefore,  the  location  of  the 
ostium  of  the  cell  and  not  the  topography  of  the  cell  itself  that  determines 
the  subclass.  From  the  standpoint  of  the  location  of  ostia,  the  anterior 
ethmoidal  cells  may  be  divided  into:  (a)  cells  communicating  with  the 
frontal  recess;  (b)  cells  communicating  with  the  ethmoidal  inf undibulum ; 
and  (c)  cells  communicating  with  the  region  of  the  ethmoidal  bulla, 
usually  the  suprabullar  recess. 

The  frontal  group  of  the  anterior  ethmoidal  cells  vary  in  number 
from  a  total  agenesis  to  three  or  four.  Developmentally  they  are  out- 
growths from  the  furrows  on  the  lateral  wall  of  the  frontal  recess  (pre- 
ethmoidal  recess  of  some  writers).  Not  infrequently  one  or  more  of  these 
cells  encroach  upon  the  lumen  of  the  frontal  sinus  to  such  an  extent  that  they 
are  ethmofrontal  cells.  Indeed,  at  times  they  are  in  reality  frontal  sinuses 
as  far  as  topography  is  concerned.  The  floor  of  the  frontal  sinus  is 
very  commonly  crowded  into  a  bullous  relief  by  frontal  ethmoidal  cells 
(Fig.  1 1 8).  Another  common  extension  of  a  frontal  cell  is  into  the  upper 
portion  of  the  agger  nasi  (Figs.  153  and  159).  Other  cells  remain  small 
and  topographically  are  in  relationship  with  the  frontal  recess  only  and 
in  this  regard  retain  their  genetic  location. 

The  frpntal  group  of  the  anterior  ethmoidal  cells  variously  impinge 
upon  the  nasofrontal  duct  or  in  the  absence  of  the  latter  upon  the  ostium 
of  the  frontal  sinus.  Not  infrequently  they  cause  the  nasofrontal  duct 
to  pursue  a  tortuous  or  serpentine  course;  moreover,  so  restrict  the  duct 
and  ostium  of  the  frontal  sinus  that  its  drainage  is  very  much  impaired 
(Fig.  128).  The  individual  cells  of  the  frontal  group  usually  communicate 
rather  freely  with  the  frontal  recess  immediately  cephalic  and  ventral  to 
the  termination  of  the  semilunar  hiatus  of  the  ethmoidal  infundibulum. 
They  are  located  between  the  lateral  surface  of  the  lamella  of  the  middle 
nasal  concha,  the  ventral  and  medial  surface  of  the  ethmoidal  bulla,  and 
the  medial  wall  of  the  bony  orbit.  It  is  particularly  these  cells  that  must 
be  ablated  in  the  endonasal  surgical  approach  of  the  frontal  sinus. 


ANTERIOR  ETHMOIDAL  CELLS  217 

The  infundibular  group  of  the  anterior  ethmoidal  cells  all  grow  from 
the  ethmoidal  infundibulum  and  in  the  adult  are  always  in  communication 
with  it.  They  vary  in  number  from  a  total  absence  to  three  or  four. 
In  a  large  percentage  of  cases  the  ventral  and  cephalic  extremity  of  the 
ethmoidal  infundibulum  ends  blindly  by  dilating  into  an  anterior 
ethmoidal  cell  (infundibular)  lateral  to  the  frontal  recess  and  its  related 
cells  (Fig.  124).  Another  very  frequent  outgrowth  from  the  ethmoidal 
infundibulum  is  into  the  agger  nasi  which  usually  more  or  less  overlies  the 
lacrimal  sac,  and  in  the  endonasal  surgical  approach  of  the  lacrimal  sac 
(dacryocystorhinostomy)  it  is  usually  opened  into  before  the  lacrimal 
bone  is  reached  in  the  operation  (Figs.  159  and  175).  Infundibular  cells 

Recessus  sphenoicialis(C.ttthmoidalis  post.) 
opticurtt .. 


Sinus  sphvnoidalis . 


C.etk?noida,lis  post. 

FIG.  155.  —  A  sagittal  section  through  the  sphenoidal  sinus  and  a  posterior  ethmoidal  cell.  Par- 
ticularly note  the  extension  of  the  posterior  ethmoidal  cell  (recessus  sphenoidalis)  over  the  sphenoidal 
sinus  into  the  body  of  the  sphenoid  bone.  The  extension  of  the  ethmoidal  cell  comes  into  intimate 
relationship  with  the  optic  foramen  and  the  contained  optic  nerve. 

may  stop  short  of  the  agger  nasi  and  more  or  less  hollow  out  the  base  of  the 
ventral  portion  of  the  uncinate  process,  particularly  where  the  uncinate 
process  and  the  ethmoidal  bulla  are  confluent.  Additional  infundibular 
cells  may  grow  from  the  ventral  and  cephalic  extremity  of  the  ethmoidal 
infundibulum,  but  they  are,  as  a  rule,  small.  It  has  been  suggested 
(Mosher)1  that  the  frontal  sinus  may  be  probed  with  greater  ease  by 
passing  through  the  larger  agger  cell  instead  of  going  first  lateral  to 

*A  Method  of  Obliterating  the  Nasofrontal  Duct  and  Catheterizing  the  Frontal  Sinus,  The 
Laryngoscope,  Vol.  21,  September,  1911. 


218  THE  ETHMOIDAL  CELLS 

the  middle  nasal  concha.  This  would  appear  correct  since  not  infrequently 
this  cell  is  of  goodly  dimension. 

The  bullar  group  of  the  anterior  ethmoidal  cells  arise  genetically 
from  the  suprabullar,  bullar,  and  infrabullar  furrows.  Relatively  few  cells 
develop  from  the  infrabullar  furrow,  a  slightly  larger  percentage  from  the 
bullar  furrow,  and  almost  constantly  (95  per  cent,  of  cases)  from  the 
suprabullar  furrow.  These  cells  variously  pneumatize  the  ethmoidal 
bulla  and  cause  it  to  be  shell-like.  Moreover,  it  is  to  these  cells  that  the 
bulla  owes  it  size  and  shape.  Since  the  larger  percentage  of  bullar  cells 
develop  from  the  suprabullar  recess  (see  page  30),  in  the  adult  most  of  them 
have  their  ostia  of  communication  located  between  the  ethmoidal  bulla  and 
the  attached  border  of  the  middle  nasal  concha.  The  number  of  cells  that 
develop  from  the  suprabullar  recess  varies  from  one  large  cell  to  four  smaller 
cells.  The  most  ventral  of  these  cells  encroach  upon  cells  of  the  frontal 
recess,  even  upon  the  frontal  sinus.  Indeed,  not  infrequently  the  most 
ventral  bullar  cell  pneumatizes  beyond  the  ethmoidal  field  between  the 
two  plates  of  the  supraorbital  wall,  whereof,  it  is  frontal  in  topography. 
The  most  dorsal  of  the  bullar  cells  very  commonly  encroach  upon  certain 
of  the  posterior  ethmoidal  cells;  indeed,  may  topographically  be  in  the 
position  of  such  cells.  Careful  dissection,  however,  shows  that  they  com- 
municate with  the  suprabullar  furrow  of  the  middle  meatus  and  are,  there- 
fore, cells  of  the  anterior  ethmoidal  group.  As  stated  elsewhere,  it  is  the 
point  of  drainage,  e.g.,  the  location  of  the  ostium  or  aperture,  rather  than 
the  topographic  position  of  an  ethmoidal  cell  that  determines  its  classifica- 
tion. The  position  of  a  cell  is  at  times  very  misleading  since  it  may  extend 
far  beyond  the  confines  of  its  allotted  field. 

The  frontal  bulla  (bulla  frontalis)  is  usually  an  upward  bleb -like  swell- 
ing or  expansion  of  one  or  more  cells  of  the  anterior  ethmoidal  group  into 
the  floor  of  the  frontal  sinus.  Multiple  frontal  bullae  at  times  mould  the 
floor  of  the  frontal  sinus.  The  ethmoidal  bulla  (bulla  ethmoidalis)  may  so 
extend  its  boundaries  by  enlargement  of  its  contained  cell  or  cells  that  it 
balloons  into  the  dorsal  part  of  the  floor  of  the  frontal  sinus  and  forms  a 
conspicuous  frontal  bulla;  moreover,  markedly  encroaches  upon  the  con- 
fines of  the  frontal  sinus.  Again  the  frontal  encroaching  cells  may  be 
outgrowths  from  the  ethmoidal  infundibulum  (inf undibulum  ethmoidale) , 
e.g.,  infundibular  cells  (see  page  213  for  their  classification).  The  anterior 
ethmoidal  cells  that  develop  from  the  frontal  recess  nearly  always  encroach 
upon  the  frontal  sinus  or  its  duct,  and  at  times  to  such  an  extent  that  one 
or  other  cell  assumes  the  dignity  of  a  frontal  bulla  (Figs.  117  and  118). 

It  must  not  be  forgotten,  however,  in  this  connection  that  the  balloon- 


POSTERIOR  ETHMOIDAL  CELLS  219 

like  swelling  frequently  encountered  in  the  floor  of  one  or  the  other  of  the 
frontal  sinuses  may  prove  to  be  a  frontal  sinus  and,  indeed,  the  only  frontal 
sinus  of  that  side  (see  page  152  and  Fig.  85). 

The  Posterior  Ethmoidal  Cells  (cellulae  ethmoidales  posterior).— 
The  posterior  ethmoidal  cells  genetically  arise  from  the  superior  and  first 
supreme  nasal  meatuses  and  in  the  adult,  therefore,  communicate  with 
the  nasal  fossa  above  the  attached  border  of  the  middle  nasal  concha,  either 
with  the  superior  nasal  meatus  or  with  the  first  supreme  nasal  meatus.  It 
should  be  recalled  that  the  first  supreme  nasal  meatus  is  present  in  ap- 
proximately 60  per  cent,  of  adult  nasal  fossae  and  that  in  75  per 
cent,  of  these  cases  a  posterior  ethmoidal  cell  communicates  with  it;  indi- 
cating, therefore,  that  the  posterior  ethmoidal  cell  in  question  arose  from 
the  first  supreme  nasal  meatus  (see  page  23).  The  superior  nasal  meatus 
never  fails  according  to  the  author's  series  of  specimens  to  give  rise  to  one 
or  more  posterior  ethmoidal  cells.  These  cells  variously  pneumatize 
and  make  shell-like  the  lateral  ethmoidal  mass  above  the  attached  border 
of  the  middle  nasal  concha.  Not  infrequently  these  cells  extend  beyond 
the  confines  of  the  ethmoidal  field  and  form  ethmomaxillary,  ethmo- 
sphenoidal  and  ethmofrontal  cells.  Moreover,  the  posterior  and  anterior 
groups  of  ethmoidal  cells  overlap  each  other's  fields  as  regards  topography, 
but  not,  as  stated  elsewhere,  as  regards  the  drainage  of  the  two  groups. 

There  is  no  constancy  in  the  number  of  posterior  ethmoidal  cells  that 
are  differentiated,  the  author  finding  them  to  vary  from  one  to  seven. 
Not  infrequently  the  posterior  ethmoidal  labyrinth  when  composed  of 
but  one  or  two  cells  occupies  as  much  space  as  when  composed  of  five,  six 
or  seven  cells.  It  does,  however,  mean  when  few  cells  are  present  that 
they  are  correspondingly  much  larger  than  the  average. 

Very  commonly  the  posterior  ethmoidal  labyrinth  is,  however,  not 
confined  to  the  lateral  ethmoidal  mass.  The  extensions  of  its  cells  into 
the  ethmoidal  appendages  (major  and  minor  conchae  or  turbinates)  will 
be  discussed  in  subsequent  paragraphs  under  the  caption  "conchal  cells." 
In  the  discussion  of  duplication  of  the  maxillary  sinus  (page  1 1 8)  mention 
was  made  of  the  very  common  extension  of  a  posterior  ethmoidal  cell  into 
the  dorsal  and  cephalic  and  medial  angle  of  the  body  of  the  maxilla.  Such 
an  ethmoidal  extension  pneumatizes  into  the  body  of  the  maxillary  bone 
at  the  expense  of  the  maxillary  sinus.  Moreover,  it  anatomically  simu- 
lates a  duplication  of  the  maxillary  sinus.  Careful  study,  however,  indi- 
cates its  true  genesis  as  a  posterior  ethmoidal  cell  and  that  it  nearly  always 
communicates  with  the  superior  nasal  meatus.  This  "ethmomaxillary" 
posterior  ethmoidal  cell  develops  variously,  at  times  occupying  a  relatively 


220  THE  ETHMOIDAL  CELLS 

small  portion  of  the  maxilla  where  the  infraorbital  and  infratemporal 
surfaces  meet,  immediately  ventral  to  the  pterygopalatine  (pterygomaxil- 
lary)  fossa.  At  other  times  the  ethmomaxillary  cell  may  assume  large 
proportions,  occupying  from  a  fourth  to  a  half  of  the  body  of  the  maxilla. 
The  maxillary  sinus  is,  of  course,  proportionately  reduced  in  size  (Fig.  101). 
It  is,  moreover,  obvious  that  an  ethmomaxillary  cell  if  of  considerable  size 
is,  from  a  clinical  viewpoint,  more  maxillary  than  ethmoidal  despite  its 
origin  from  the  ethmoid  bone.  The  ethmomaxillary  cell  (or  better  sinus,  if 
large)  has  its  ostium  or  aperture  located  at  its  most  cephalic  point,  normally 
in  the  superior  nasal  meatus;  and,  not  unlike  the  ostium  of  the  maxillary 
sinus,  is  very  disadvantageously  located  for  efficient  drainage,  e.g.,  gravity 
drainage  is  wholly  absent  in  the  usual  upright  posture  of  the  body.  In 
disease,  a  goodly  sized  ethmomaxillary  sinus  doubtless  behaves  like  the 
maxillary  sinus  proper.  The  operator  must,  however,  remember  that  in 
all  likelihood  a  healthy  maxillary  sinus  proper  would  be  opened  into  in 
an  empyema  of  the  ethmomaxillary  sinus  unless  a  rhinoscopic  and 
skiagraphic  study  preceded  the  operation. 

In  the  more  usual  and  moderately  sized  posterior  ethmoidal  cells 
the  optic  nerve  at  the  optic  foramen  is  separated  from  the  most  dorsal 
and  superior  of  the  cells  by  bone  from  2  to  5  mm.  in  thickness. 
The  ethmoid  labyrinth  being  placed  in  the  sagittal  plane,  the  optic  nerve 
as  it  courses  toward  the  eyeball  diverges  more  and  more  from  the  posterior 
ethmoidal  cells  as  one  passes  from  the  optic  foramen  toward  the  eyeball. 
Not  infrequently  certain  of  the  posterior  ethmoidal  cells  invade  the  sphe- 
noid bone  in  the  formation  of  ethmosphenoidal  cells  (Fig.  141).  The 
latter  extend  variously  dorsalward  into  the  body  and  lesser  wing  of  the 
sphenoid  bone  over  the  sphenoidal  sinus;  indeed,  may  extend  sufficiently 
far  to  come  into  very  intimate  relationships  with  the  optic  nerve  at  the 
optic  foramen  and  for  a  considerable  distance  in  front  of  it.  The  lamella  of 
bone  intervening  between  the  mucous  membrane  of  the  ethmosphenoidal 
cell  or  sinus  and  the  optic  nerve  is  not  infrequently  reduced  to  a  tissue- 
paper  delicacy.  Indeed,  the  lamella  of  bone  may  be  deficient  at  places  so 
that  the  optic  nerve  is  directly  exposed  to  the  mucous  membrane  of  the 
ethmosphenoidal  cell.  The  importance  of  this  not  infrequent  very  inti- 
mate relation  between  certain  of  the  posterior  ethmoidal  cells  and  the 
optic  nerve  must  be  thought  of  in  connection  with  blindness  of  nasal  origin. 

These  sphenoethmoidal  cells  are  at  times  of  such  a  size  that  they 
replace  almost  entirely  the  sphenoidal  sinuses  and,  therefore,  preclude 
the  sphenoidal  sinuses  from  establishing  the  usual  relationships  with  the 
optic  nerve.  Just  as  the  optic  nerve  at  times  courses  almost  within  the 


COXCHAL  CELLS  22 1 

lumen  of  the  sphenoidal  sinus  (Fig.  140),  it  may  be  almost  entirely  sur- 
rounded by  an  extensively  developed  posterior  ethmoidal  cell  which  has 
pneumatized  into  the  body  and  lesser  wing  of  the  sphenoid  (Fig.  155). 

The  extension  of  posterior  ethmoidal  cells  into  the  frontal  bone  is 
extremely  commonplace.  They  usually  extend  dorsal  to  the  frontal  sinus 
proper  for  a  greater  or  less  distance  over  the  orbit  and  are,  therefore, 
frequently  called  ethmoorbital  or  ethmofrontal  cells. 

Occasionally  the  posterior  ethmoidal  cells  so  develop  and  arrange 
themselves  that  they  form  the  boundaries  of  the  pterygopalatine  (ptery- 
gomaxillary)  fossa  and  thereby  replace  the  more  usual  maxillary  sinus 
boundary  in  front  and  the  sphenoidal  sinus  boundary  above  and  behind 
(see  pages  179,  318  and  319).  It  is,  therefore,  wholly  possible  that  the 
sphenopalatine  or  nasal  ganglion  of  Meckel  be  at  times  exposed  to  the  influ- 
ences of  the  posterior  ethmoidal  labyrinth,  both  in  health  and  disease. 

The  Conchal  Cells  (cellulae  conchales).1 — Not  infrequently  cells  of 
both  the  anterior  and  posterior  ethmoidal  groups  grow  into  the  concha 
nasalis  media,  the  agger  nasi,  and  the  processus  uncinatus.  It  is  to  this 
group  of  cells  that  the  name  cellulae  conchales  is  applied.2  Such  cell  ex- 
tensions may  be  single  or  multiple,  both  unilaterally  and  bilaterally. 
It  must,  however,  be  stated  at  the  outset  that  these  cells  do  not  differ  in 
any  manner,  save  in  their  location,  from  the  posterior  ethmoidal  cells 
which  make  shell-like  the  superior  and  supreme  conchse,  and  the  anterior 
ethmoidal  cells  which  pneumatize  to  a  papery  delicacy  the  ethmoidal  bulla. 

Since  the  time  of  Santorini,  who  apparently  was  the  first  anatomist  to 
call  attention  to  the  cavity  frequently  found  in  the  middle  nasal  concha, 
many  conflicting  and  erroneous  hypotheses  have  been  advanced  as  to  the 
nature  and  origin  of  these  spaces.  Many  of  the  theories  are  from  the 
pens  of  earlier  clinicians  who  removed  at  operation  portions  of  the  walls 
of  such  cavities  that  were  changed  by  pathological  processes  and  attempted 
to  explain  the  origin  of  these  spaces  by  a  faulty  interpretation  of  the  al- 
tered tissue  removed.  The  cavities  have  been  variously  termed  cysts, 
abscesses,  osseous  cysts,  exostoses,  neoplasms,  ectasias  of  the  ethmoid 
bone,  aberrated  ethmoidal  cells,  and  when  large  and  occurring  in  the 
ventral  portion  of  the  concha  media,  as  conchse  bullosse. 

1  H.  A.  Lothrop,  Annals  of  Surgery,  Vol.  38,  1903. 

George  E.  Shambaugh,  Trans.  Amer.  Laryngol.  Assoc.,  1907. 
J.  Parsons  Schaeffer,  Anat.  Rec.,  1910. 
Glasmacher,  Berliner  Klin.  Wochenschr.,  1884. 
Depuytren,  Clinique  Paris,  Vol.  n,  1830. 

2  J.  Parsons  Schaeffer:  On  the  Genesis  of  Air  Cells  in  the  Conchae  Nasales,  Anat.  Record.  Vol.  4, 
No.  4,  1910. 


222  THE  ETHMOID AL  CELLS 

In  order  to  better  understand  these  cells  and  to  see  that  they  are 
nothing  other  than  ethmoidal  cells,  it  is  essential  that  the  origin  of  the 
ethmoidal  labyrinth  be  kept  in  mind.  The  location  of  these  cells  appears 
less  abnormal  when  one  recalls  that  the  ethmoidal  conchae  and  the  proc- 
essus  uncinatus  are  merely  appendages  of  the  lateral  ethmoidal  masses. 
There  is  no  reason,  therefore,  why  ethmoidal  cells  should  not  at  times  in 
the  formation  of  the  ethmoidal  labyrinth  grow  into  the  appendages  jusl 
as  they  grow  into  the  lateral  ethmoidal  masses  proper. 

According  to  the  author's  reconstructions1  of  the  lateral  wall  of  the 
nasal  cavity  of  different  aged  fetuses,  the  primitive  ethmoturbinal  fold, 
with  its  subsequent  modifications,  is  not  concerned  only  in  producing  the 


FIG.   156.  FIG.   157.  FIG.   158. 

FIGS.   156,  157  and  158. — Frontal  sections  of  the  left  nasal  fossa  in  the  region  of  the  bulla  ethmoidalis 

from  a  term  fetus  (series  D,  slides  5,  6  and  7). 

Note  the  development  of  ethmoidal  cells  in  the  concha  media  and  the  bulla  ethmoidalis.  None  of 
the  sections  is  far  enough  ventrad  to  pass  through  the  ostium  of  the  maxillary  sinus. 

C  =  cellulae  ethmoidales;  M.n.m.  =  meatus  nasi  medius;  M.n.i.  =  meatus  nasi  inferior;  C.n.med. 
=  concha  nasalis  media;  B.  eth.  =  bulla  ethmoidalis;  Inf.  eth.  =  infundibulum  ethmoidale;  Proc. 
unc.  =  processus  uncinatus;  5.  max.  =  sinus  maxillaris;  F.  cr.  ant.  =  fossa  cranii  anterior. 

ethmoidal  conchae  and  the  intervening  furrows  (meatuses),  but  also  with 
the  structures  operculated  by  the  concha  nasalis  media,  e.g.,  the  processus 
uncinatus,  the  bulla  ethmoidalis,  the  hiatus  semilunaris,  and  the  in- 
fundibulum ethmoidale.  These  modifications  are  all  intimately  related 
to  the  rudiments  of  the  paranasal  sinuses. 

The  posterior  group  of  ethmoidal  cells  are  primarily  constricted  from 
or  are  direct  extensions  of  the  furrows  separating  the  primitive  ethmoidal 
conchae,  and  the  anterior  group  of  ethmoidal  cells  develop  from  preformed 

1  Loc.  cit. 


CONCHAL  CELLS 


223 


accessory  furrows  of  the  middle  meatus;  therefore,  are  in  relation  to  the 
furrows  and  folds  found  in  this  location.  In  this  connection  it  is  an  in- 
teresting fact  to  note  that  the  ostia  of  conchal  cells  invariably  communicate 
directly  or  indirectly  with  the  points  from  which  ethmoidal  cells  normally 
develop.  Moreover,  a  study  of  a  series  of  specimens  proves  that  conchal 
cells  are  either  parts  of  other  ethmoidal  cells  which  determine  their 
nasal  connection  or  they  communicate  (a)  directly  with  the  superior 


Sinus  s 


yhenaukdis  dexter       Sinus  spheTwidati*  sinistei 


IK 


Sinus  frontaUs 
Frontal  cells 
frontalis 

Agger  nasi  cell 
fundibular  cell) 


,.Saccu,s 

(dotted  outline) 

....  -  •  Cc.  concha],  e  s 


IH%W5  cavemosi 


FIG.  159. — The  lateral  nasal  wall  with  the  paranasal  sinuses  exposed,  the  maxillary  sinus  excepted. 
Especially  note  the  extension  of  posterior  ethmoidal  cells  (Cc.  conchales)  into  the  middle  nasal  concha. 
Moreover,  note  how  the  cell  in  the  agger  nasi  overlays  the  lacrimal  sac.  In  the  endonasal  approach  of 
the  lacrimal  sac  and  nasolacrimal  duct  it  is  this  cell  that  is  opened  into  first.  The  condition  is 
common.  The  erectile  character  of  the  mucous  membrane  is  marked  over  the  inferior  and  middle 
concha?. 

meatus,  (b)  with  the  infundibulum  ethmoidale,  or  (c)  directly  with  the 
ventral  end  of  the  middle  meatus.  The  ostia  in  the  latter  case  are  on  the 
lateral  surface  of  the  concha  nasalis  media. 

Although  the  rudiments  of  the  ethmoidal  cells  are  primarily  constric- 
tions or  extensions  from  the  nasal  fossae,  the  further  extension  and  develop- 
ment of  these  cells  depend  upon  the  simultaneous  processes  of  growth 
(of  the  sacs)  and  resorption  (of  surrounding  tissue).  In  this  manner  the 


224  THE  ETHMOIDAL  CELLS 

cells  extend  farther  and  farther  into  the  lateral  masses  of  the  ethmoid 
bone  as  age  advances,  and  in  the  adult  are  completed  by  the  articulation 
of  the  ethmoid  bone  with  the  frontal,  lacrimal,  sphenoid,  maxillary,  and 
palate  bones.  These  developmental  processes  are  not  uniform  and, 
doubtless,  are  carried  farther  in  some  cases  than  in  others,  henc?  the 
extension  of  ethmoidal  cells  not  only  farther  into  the  lateral  mass  of  the 
ethmoid  bone,  but  also  into  its  appendages,  such  as  the  ethmoidal  conchae, 
the  processus  uncinatus,  etc. 

A  reference  to  Figs.  159  and  160  shows  the  extension  of  the  inferior 
ethmoidal  groove  (superior  nasal  meatus)  not  only  into  the  lateral  eth- 
moidal mass,  but  also  into  the  concha  media,  thus  forming  conchal  cells 


Cc.conchales  » 
(concha,  •media.) 

•Sinus 


FIG.    1 60. — A  frontal  section  through  the  skull  of  an  adult.      Note  the  supraorbital  extensions  of  the 
frontal  sinuses  and  the  large  ethmoidal  cells  in  the  middle  nasal  conchas. 

which  are  merely  parts  of  the  more  usual  posterior  lateral  mass  cells.  At 
first  thought  it  may  seem  difficult  to  account  for  the  conchal  cells  having 
their  ostia  opening  inferior  to  the  attachment  of  the  concha  media,  either 
into  the  middle  meatus  or  the  ethmoidal  infundibulum.  However,  when 
one  recalls  the  great  modifications  of  this  portion  of  the  middle  meatus 
overhung  by  the  concha  media,  incident  to  the  formation  of  the  struc- 
tures found  there,  and  that  the  anterior  group  of  ethmoidal  cells  have 
their  origin  in  this  position,  it  is  not  difficult  to  see  why  some  of  these 
cells  extend  not  only  into  the  lateral  mass  of  the  ethmoid  bone,  but  also  into 
the  processus  uncinatus,  the  concha  media,  and  the  agger  nasi. 

In  Fig.  158  is  represented  a  photograph  of  a  specimen  in  which  a 
conchal  cell  is  already  present  in  the  concha  nasalis  media  of  a  fetus  at 


CONCHAL  CELLS 


225 


term.  Of  course,  most  conchal  cells  must  necessarily  appear  compara- 
tively late  in  the  formation  of  the  ethmoidal  labyrinth,  since  the  positions 
they  occupy  with  reference  to  the  ethmoidal  cell  rudiments  are  relatively 
far  removed.  The  extensions  into  the  conchae,  etc.,  would,  therefore, 
in  most  cases  be  delayed  probably  until  puberty,  or  even  later,  when  the 
ethmoidal  labyrinth  reaches  its  full  development.  Knight's  statement: 


f/vccssits  fro//. f a/is . 


asale 


„ 

Iroecssus  vncinatui, 
Bulla  etkmoidaMs'' 
Condi u,  7iasulis  medi 

Cundta 


FIG.  161. — An  enormously  developed  bulla  ethmoidalis  as  seen  through  the  osseous  pyriform  nasal 
aperture.  Note  that  the  uncinate  process  is  crowded  caudo-laterally  and  the  concha  nasalis  media 
thinned  out  and  crowded  against  the  septum  nasi.  Obviously  the  enlarged  bulla  was  the  prime 
factor  in  the  deviation  of  the  septum. 

"Children  seem  to  be  exempt.  None  of  the  patients  was  under  20  years 
of  age,"  is  misleading.  If  late  fetuses  show  conchal  cells  (Fig.  158)  surely 
children  are  not  exempt. 

Extensions  of  ethmoidal  cells  (infundibular)  into  the  agger  nasi  are 
not  uncommon  (Figs.  153  and  159).  There  is  no  reason  why  cells  in  this 
location  could  not  extend  farther  and  finally  reach  and  occupy  the  ventral 


226  THE  ETHMOIDAL  CELLS 

end  of  the  concha  inferior.  Such  an  extension  would  explain  Schaeffer's 
cell  of  the  ventral  end  of  the  inferior  nasal  concha.  The  writer  finds 
that  cells  in  the  latter  position  are  extremely  rare. 

Careful  examination  of  conchal  cells  shows  that  they  do  not  differ 
in  any  manner  from  the  ethmoidal  cells  of  the  lateral  masses.  This  is 
true  macroscopically  and  microscopically.  The  mucous  membrane  lining 
conchal  cells  is  extremely  thin,  but  corresponds  in  its  general  structure 
to  that  lining  the  other  ethmoidal  cells,  unless  changed  by  a  pathological 
process.  It  must  be  remembered  that  conchal  cells,  like  any  of  the 
ethmoidal  cells  or  of  the  paranasal  sinuses,  may  become  the  seat  of  an 
empyema  or  a  mucocele,  and  enlarge,  because  the  ostia  of  these  cells  are 
invariably  placed  at  the  highest  points  of  the  cavity  and  very  disadvan- 
tageously  placed  as  drainage  openings,  a  fact  easily  understood  when  their 
development  is  considered.  The  existence  of  air  cells  in  the  conchae, 
etc.,  is  certainly  not  the  result  of  an  empyema  or  rarefying  osteitis, 
but  because  these  cells  are  normally  found  in  these  positions  they  may 
become  the  seat  of  pathological  conditions  just  as  do  other  cells  of  the 
ethmoidal  labyrinth. 

Sex  does  not  have  any  bearing  on  the  development  of  conchal  cells, 
and  they  are  about  equally  divided  as  to  whether  the  ostia  open  cephalic 
or  caudal  to  the  attached  border  of  the  concha  nasalis  media. 

Santorini1  thought  conchal  cells  (referring  to  the  concha  media) 
quite  common,  but  says  he  should  not  venture  to  say  that  the  condition 
was  constant.  He  apparently  regarded  these  cells  much  more  frequent 
than  they  really  are.  According  to  Reardon,  Zuckerkandl  observed  them 
8  times  in  172  skulls.  Knight  says  that  Zuckerkandl  "found  them  36 
times  in  200  postmortem  examinations."  Lothrop  found  them  in  9 
per  cent,  of  all  cas^s.  The  author  in  an  examination  of  over  200  adult 
nasal  fossae  found  conchal  cells  in  approximately  12  per  cent,  of  the 
specimens. 

The  Middle  Conchal  Sinus. — The  so-called  middle  conchal  sinus 
(a  pseudo  paranasal  sinus),  formed  by  the  lateral  and  superior  curling 
of  the  free  border  of  the  concha  media,  is  not  homologous  with  nor  analo- 
gous to  the  conchal  cells.  Nevertheless,  in  some  cases  it  may  retain 
fluid  in  its  hammock-like  fold;  indeed,  may  become  the  seat  of  an  empyema 
or  a  mucocele.  The  majority  of  middle  conchae  do  not,  however,  sho\v  the 
sinus  and  when  present  it  is,  as  a  rule,  of  minor  importance  (Fig.  162). 

Concluding  Considerations. — As  may  be  inferred  from  the  foregoing 
paragraphs,  it  is  difficult  in  skiagrams  to  distinguish  the  anterior  ethmoidal 

1  Dominici  Joannes  Santorini:  Observations  Anatomicae,  pp.  88-89,  1739. 


CONCLUDING  CONSIDERATIONS 


227 


cells  from  the  frontal  sinus  in  the  early  postnatal  period.  This  is,  of 
course,  due  to  the  genetic  and  early  intimate  topographic  relationships 
between  the  most  ventral  of  the  ethmoidal  cells  and  the  frontal  sinus 
(Figs.  36  and  37).  The  fact  that  the  skiagram  fails  to  differentiate  the 
frontal  sinus  at  this  early  period  is  of  little  importance  clinically  since  both 
the  frontal  sinus  and  the  anterior  ethmoidal  cells  in  diseased  states  are 
doubtless  conjointly  involved.  The  nature  of  the  anatomy  of  the  region 

Ckiasma,  o 

Cc.  ejhmoidales 


PIG.  162. — A  sagittal  section  through  the  ethmoidal  labyrinth,  sphenoidal  sinus,  frontal  sinus  and 
the  'hypophysis  cerebri.  Especially  note  the  pseudo  paranasal  sinus  (sinus  conchae  mediae)  in  the 
middb  concha  (see  text,  page  226). 

(early  childhood  period  of  the  frontal  recess  and  its  derivatives)  is  such  that 
the  simultaneous  involvement  of  all  cellular  outgrowths  is  certain.  The 
skiagram  does  reveal  the  frontal  recess  with  its  paranasal  derivatives  and 
treatment  must  be  directed  to  the  region  rather  than  to  an  individual 
cell  or  sinus  at  this  early  time.  Indeed,  it  may  not  be  until  the  second 
year  of  infancy  that  one  is  certain  which  part  of  the  frontal  recess  or  which 
ethmoidal  cell  is  really  destined  to  become  topographically  the  frontal 


228  THE  ETHMOIDAL  CELLS 

sinus.  Despite  this,  it  must,  however,  be  recalled  that  the  rudiment  of  the 
frontal  sinus  is  far  advanced  long  before  this  period  (see  embryology, 
Chapter  I).  Of  course,  after  the  second  year  the  frontal  sinus  rapidly 
assumes  larger  dimensions  and  begins  to  pneumatize  well  beyond  the 
confines  of  the  frontal  recess,  so  that  it  is  not  infrequently  clearly  indicated 
as  such  on  X-ray  pictures. 

The  ethmoidal  cells  in  children  often  appear  indistinct  and  blurred 
in  skiagrams.  Electrical  transillumination  appears  to  be  utterly  unre- 
liable. Rhinoscopic  examination  of  the  ethmoidal  field  is  practised  with 


FIG.   163. — The  bony  orbit,  the  medial  wall  of  which  bears  intimate  relationships  to  the  paranasal 

sinuses. 

I    =  frontal;    2    =  nasal;   3  and  II   =  maxilla;   4  =  lacrimal;   5    =  ethmoid;   6,   8  and  9  =  sphenoid; 
7    =  palate;  10  =  zygomatic. 

great  difficulty  during  the  early  childhood  period  owing  to  the  limited 
size  of  the  nasal  fossae,  and  Haike  is  convinced  that  despite  its  limitations 
the  skiagram  offers  the  only  reliable  diagnosis  of  ethmoidal  affections  in 
children. 

Despite  the  fact  that  the  nasal  fossae  and  its  meatuses  are  relatively 
narrow  in  young  children,  making  the  endonasal  approach  and  exposure  of 
the  ethmoidal  labyrinth  difficult,  both  the  anterior  and  posterior  groups 
of  ethmoidal  cells  are  of  goodly  size  even  during  the  first  years  of  postnatal 
life  and  rapidly  assume  larger  dimensions  as  age  advances  (see  Table  L, 
page  211).  While  the  anatomy  of  the  early  nasal  cavity  is  such  that 


CONCLUDING  CONSIDERATIONS 


229 


endonasal  treatment  of  the  ethmoidal  cells  must  be  limited  in  large  meas- 
ure to  irrigation,  it  cannot  be  gainsaid  that  the  location  and  relatively 
advanced  state  of  development  of  the  ethmoidal  labyrinth  justify  radical 
operations  when  the  endonasal  methods  fail.  In  this  connection  it  is, 
of  course,  necessary  to  recall  the  relations  of  the  ethmoidal  labyrinth 
other  than  its  nasal  exposure.  The  ethmoidal  cells  have  been  operated 


Sinus  front  a  Us 


Cellulae  ethmoidales 

Simis  gphenoidalu 


Concha 
media 


Septum  nasi 


its  nasi 
superior 


Meatus  nasi 
medius 


Sinus  maxillaru 


\Concha  nasaiis 
inferior 


FIG.   164. — A  dissection  of  the  paranasal  sinuses.     The  lining  mucous  membranes  are  represented. 
The  cadaver  was  first  formalized,  then  the  osseous  boundaries  were  removed  piecemeal. 

upon  in  children  by  way  of  the  nasal  cavity,  the  frontal  sinus,  the  maxil- 
lary sinus,  and  the  medial  side  of  the  orbit  (resection  of  the  orbital  plate, 
lamina  papyracea).  The  early  intimate  anatomic  relationships  between 
the  ethmoidal  cells  and  the  orbital  cavity  must  always  be  recalled  in 
ethmoidal  affections.  Radical  operations  have  been  performed  on  the 
ethmoidal  cells  in  children  as  young  as  30  months  of  age1  and  more  fre- 

1  E.  Myer,  Berliner  Klin.  Wochenschr.,  1905. 


230  THE  ETHMOIDAL  CELLS 

quently  as  age  advances  and  both  the  ethmoidal  labyrinth  and  nasal  fossa 
assume  larger  proportions. 

Transillumination  is  not  to  be  depended  upon  as  a  means  of  outlining 
the  normal  and  fully  developed  ethmoidal  labyrinth,  and  is  utterly  un- 
reliable in  ethmoidal  suppuration  in  the  opinion  of  many  investigators. 


FIG.   165. — Frontal  skiagram  of  a  dryed  skull  of  an  adult.      Note  the  paranasal  sinuses.      The  prepara- 
rations  shown  in  Figs.  165,  166,  and  I66A  were  *-rayed  by  Prof.    Manges. 


Roentgenography,  on  the  other  hand,  is  of  distinct  value  in  the  study 
of  the  normal  ethmoidal  labyrinth,  despite  its  limitations.  Especially 
are  skiagrams  of  value  in  the  delineation  of  the  anterior  group  of  ethmoidal 
cells  in  their  relationships  with  the  floor  of  the  frontal  sinus.  Moreover, 


CONCLUDING  CONSIDERATIONS 


231 


such  pictures  are  desirable  when  the  endonasal  approach  of  the  frontal 
sinus  is  attempted. 

Fortunately  in  the  later  childhood  and  adult  periods  the  nasal  fossa 
and  meatuses  have  assumed  larger  proportions,  making  the  direct  endo- 
nasal examination  of  the  ethmoidal  field  possible  and  feasible.  Indeed, 
some  clinicians  claim  that  the  presence  of  pus  in  the  ethmoidal  cells  can 
better  be  determined  by  direct  examination  than  by  roentgenography. 


FIG.   166. — Profile  skiagram  of  a  dryed  skull. 

However,  the  skiagram  is  of  real  value  in  the  detection  of  suppuration 
and  purulent  collections.  Turner  and  Porter  have  been  unable  in  frontal 
X-ray  exposures  to  satisfy  themselves  "of  the  possibility  of  differentiating 
between  disease  of  the  anterior  and  posterior  groups  of  cells."  Moreover, 
it  is  well  known  that  profile  skiagrams  not  only  picture  the  ethmoidal 
cells  of  that  side,  but  also  the  cells  of  the  opposite  side.  This  appears  to 
interfere  with  the  recognition  with  certainty  of  unilateral  affections. 
The  experienced  roentgenologist,  however,  not  infrequently  correctly 


23  2  THE  ETHMOIDAL  CELLS 

interprets  the  ethmoidal  field  in  skiagrams.     It  is  obviously  not  a  work 
for  the  novice. 

To  obviate  the  overlapping  of  ethmoidal  cells  as  occurs  in  frontal 
skiagrams  and  the  projection  of  the  opposite  ethmoidal  labyrinth  over 
the  ethmoidal  field  under  investigation  as  occurs  in  profile  skiagrams, 
it  would  appear  that  the  methods  of  Pfahler  and  Pfeiffer  should  be  of 


FIG.  i66.4. — Profile  skiagram  of  a  sectioned  head  of  an  adult  negro.  The  paranasal  sinnses 
are  filled  with  Wood's  metal  and  are  indicated  by  the  deep  black  outlines.  The  nasolacrimal  duct 
is  shown  coursing  above  and  medial  to  the  forepart  of  the  maxillary  sinus.  The  horizontal  white 
lines  indicate  the  planes  of  section. 

distinct  advantage.  Both  of  the  methods  take  the  skiagram  through  the 
vertical  diameter  of  the  head  and  picture  both  the  complete  ventrodorsal 
and  transverse  diameters  of  the  bilateral  ethmoidal  labyrinth  with  much 
less  overlapping  and  superimposing  of  cells.  The  anatomy  of  the  eth- 
moidal labyrinth  is,  of  course,  such  in  very  many  cases  that  some  over- 


CONCLUDING  CONSIDERATIONS 


233 


lapping  of  cells  in  X-ray  pictures  is  inevitable  regardless  of  the 
exposure. 

The  anatomic  position  of  the  ethmoidal  field  is  of  great  importance 
in  diseased  states  of  its  honeycomb-like  structure.  Infection  may  readily 
extend  into  the  orbit,  giving  rise  to  an  orbital  cellulitis.  At  best  the 
orbital  plate  or  lamina  papyracea  intervening  is  of  extreme  delicacy  and 
not  infrequently  of  a  fenestrated  nature  due  to  congenital  dehiscences. 
The  very  intimate  relationship  between  certain  of  the  anterior  group  of 
ethmoidal  cells  and  the  lacrimal  fossa  and  sac  lead  to  frequent  secondary 
involvement  of  the  lacrimal  sac  (dacryocystitis)  in  ethmoidal  infection 
(see  page  253).  The  cranial  cavity  may  be  involved,  the  ethmoidal 
infection  extending  by  way  of  the  ethmoidal  veins.  The  very  intimately 
related  ophthalmic  vein  may  carry  infection  into  the  dural  cavernous 
sinus.  Occasionally,  especially  in  children,  the  small  vein  which  traverses 
the  foramen  caecum  infects  the  superior  sagittal  or  longitudinal  dural 
sinus. 

The  location  of  many  of  the  anterior  group  of  ethmoidal  cells  is 
such  that  they  drain  directly  or  indirectly  into  the  inf  undibulum  ethmoidale 
and  from  there  through  the  ostium  maxillare  into  the  maxillary  sinus. 
The  latter  may,  therefore,  become  a  cesspool  for  infectious  materials  from 
certain  of  the  cells  of  the  ethmoidal  labyrinth  (see  also  frontal  sinus, 
page  172). 

The  very  common  extensions  of  the  ethmoidal  cells  into  the  middle 
nasal  concha,  the  uncinate  process,  the  agger  nasi,  etc.,  must  not  be  for- 
gotten in  dealing  with  the  bleb-like  enlargements  of  these  structures 
(page  225).  Moreover,  the  extension  of  certain  ethmoidal  cells  into 
neighboring  bones  is  of  distinct  clinical  importance,  especially  those  that 
simulate  maxillary  and  sphenoidal  sinuses  (see  pages  219,  220).  It  is 
equally  important  clinically  to  recall  that  many  of  the  ethmoidal  cells 
have  no  gravity  drainage  in  the  more  usual  postures  of  the  body.  In 
this  regard  such  cells  are  not  unlike  the  maxillary  and  sphenoidal  sinuses. 
Some  of  the  ethmoidal  cells,  however,  have  dependent  or  gravity  drain- 
age and  are  not  unlike  the  frontal  sinus  in  this  respect. 


VII-THE  NASOLACR1MAL  PASSAGEWAYS 


CHAPTER  VII 
THE   NASOLACRIMAL  PASSAGEWAYS 

The  lacrimal  sac  (saccus  lacrimalis)  and  the  nasolacrimal  duct  (ductus 
nasolacrimalis)  are  very  intimately  related  to  the  lateral  wall  of  the  nasal 
fossa  and  to  certain  of  the  paranasal  (accessory)  sinuses.  The  lacrimal 
ducts  (ductus  lacrimales,  lacrimal  canaliculi)  are  not  intimately  related 
to  the  parts  in  question  save  as  they  near  and  connect  up  with  the  mem- 
branous lacrimal  sac.  Moreover,  the  nasal  fossa  serves  as  a  drainage 
chamber  for  the  lacrimal  apparatus,  receiving  the  lacrimae  or  tears  in  the 
inferior  meatus.  The  intimate  relationship  between  the  nasolacrimal 
duct  and  the  nasal  fossa  is  taken  advantage  of  surgically,  intranasal  dacry- 
ocystotomy  (dacryocystorhinostomy)  being  frequently  practised  in  steno- 
sis of  the  nasolacrimal  duct.  It  is,  therefore,  deemed  apropos  and  essential 
in  this  connection  to  analyze  the  regional  and  topographic  anatomy  of  the 
lacrimal  ducts,  the  lacrimal  sac  and  the  nasolacrimal  duct,  with  especial 
reference  to  the  nasal  fossa  and  the  related  paranasal  sinuses  and  to  refer 
to  other  developmental  and  anatomical  features  that  are  of  importance 
here. 

Genetic  and  Developmental  Anatomy. — In  order  that  the  variations 
in  the  topography  and  anatomy  of  the  fully  established  nasolacrimal  pas- 
sageways may  be  properly  interpreted,  it  is  necessary  that  one  recalls  the 
fundamental  developmental  stages  in  the  formation  of  the  channels.  As 
is  well  known,  at  one  stage  of  the  human  embryo  there  extends  a  fissure 
or  furrow,  the  naso-optic  fissure,  from  the  eye  to  the  nasal  pit.  This 
fissure  is  bounded  superiorly  by  the  embryonic  lateral  nasal  process  and 
inferiorly  by  the  embryonic  maxillary  process  (see  page  4).  The  naso- 
optic  fissure  gradually  disappears  normally  by  a  growth  and  coalescence 
of  the  structures  bordering  it.  The  coalescence  or  fusion  of  the  lateral 
nasal  and  maxillary  processes  takes  place  from  within  outward,  thereby 
"outfolding"  the  intervening  naso-optic  fissure  (Fig.  167).  The  strand 
of  thickened  epithelium  along  the  floor  of  the  now  rudimentary  naso-optic 
fissure  undergoes  further  proliferation  and  suffers  absolute  and  complete 
detachment  from  its  surface  connections  and  becomes  entirely  surrounded 
by  the  subjacent  mesenchymal  tissue  into  which  the  detached  epithelial 
cord  sinks  (Fig.  169).  The  related  and  surrounding  mesenchyme  is  des- 

237 


238 


THE  NASOLACRIMAL  PASSAGEWAYS 


tined  in  part  to  form  the  maxilla,  the  inferior  conchal  or  turbinated 
bone  and  the  lacrimal  bone.  The  surface-detached  and  mesenchymal- 
surrounded  solid  epithelial  cord  is  the  forebear  or  anlage  of  the  naso- 
lacrimal  passages.  The  original  solid  cord  grows  cephalically,  giving  rise 


nof 


FIG.  167. — Photomicrograph  of  a  frontal  section  of  the  head  of  a  human  embryo  aged  35  days. 
Note  in  the  region  of  the  naso-optic  furrow  (nof)  the  nipple-like  thickening  (d)  of  the  surface 
ectoderm  in  the  formation  of  the  rudiment  of  the  nasolacrimal  passageways.  X  7. 

normally  to  the  cupola  of  the  lacrimal  sac  and  by  secondary  outgrowths 
to  the  two  lacrimal  ducts.  Moreover,  it  grows  nasalward  and  establishes 
connections  with  the  epithelium  of  the  inferior  nasal  meatus.  The  solid 
cord  and  its  secondary  outgrowths  or  sprouts,  by  a  rearrangement  of  their 


PIG.  168. — Photomicrograph  of  a  frontal  section  of  the  head  of  a  human  embryo  aged  36  days. 
Note  the  growth  of  the  rudiment  of  the  nasolacrimal  passageways  (d)  and  compare  with  Fig.  167. 
Nof  =  remains  of  naso-optic  furrow.  X  7. 

cellular  elements,  become  hollow  and  form  the  duct  connections  between 
the  conjunctival  culdesac  and  the  inferior  meatus  of  the  nasal  fossa.  Ossi- 
fication of  the  surrounding  mesenchyme  takes  place  in  the  formation  of 
the  maxilla,  the  inferior  turbinated  and  the  lacrimal  bones,  so  that  ulti- 


DEVELOPMENT 


239 


mately  the  membranous  nasolacrimal  duct  and  the  lower  portion  of  the 
membranous  lacrimal  sac  become  encased  in  an  osseous  canal  (canalis 
nasolacrimalis)  formed  by  the  maxilla  and  the  inferior  turbinated  and  the 
lacrimal  bones.  The  lacrimal  ducts  and  the  greater  portion  of  the  lacrimal 
sac  do  not  become  encased  by  bone,  the  former  coursing  within  the  soft 
tissues  of  the  eyelids  and  the  latter  resting  in  the  shallow  lacrimal  fossa 
(Fig.  173). 

The  nasolacrimal  passageways,  at  first  solid  epithelial  cords,  ulti- 
mately become  canalized  in  an  irregular  manner.  The  canalization  is  in 
reality  nothing  other  than  a  rearrangement  of  the  epithelial  cells  around  a 
centrally  placed  lumen  rather  than  a  necrobiosis  of  central  cells.  The  ocu- 
lar end  of  the  solid  nasolacrimal  duct  is  the  first  to  establish  a  lumen.  The 
horizontal  portions  of  the  lacrimal  ducts  (canaliculi)  establish  lumina  be- 


FIG.  169. — Photomicrograph  of  a  frontal  section  of  the  head  of  a  human  embryo  aged  43  days. 
Note  the  complete  detachment  of  the  rudimentary  nasolacrimal  passageways  (d)  from  the  surface 
ectoderm.  The  "passageways"  are  solid  epithelial  cords  and  entirely  surrounded  by  mesenchymal 
tissue  at  this  time.  X  7. 

fore  the  vertical  portions  (Fig.  170).  The  point  of  coalescence  between  the 
nasal  end  of  the  solid  nasolacrimal  duct  and  the  mucous  membrane  of  the 
inferior  nasal  meatus  is  the  last  point  in  the  entire  duct  system  to  become 
patent.  In  most  instances,  canalization  here  is  deferred  until  the  end  of 
fetal  life.  Indeed,  the  author  has  made  many  observations  in  which  a 
membranous  barrier  between  the  nasolacrimal  duct  and  the  inferior  meatus 
existed  during  the  first  weeks  of  infancy  (Fig.  171). 

One  of  the  striking  features  of  the  nasolacrimal  duct  at  birth  is  its 
relatively  large  diameter  and  extremely  irregular  walls.  The  latter  condi- 
tion gradually  disappears  to  a  large  degree;. some  of  the  recesses,  however, 
developing  into  diverticula,  others  remaining  as  mucosal  shelves  and  so- 
called  valves.  The  nasolacrimal  duct  at  birth  averages  about  2  mm.  in 


240 


THE  NASOLACRIMAL  PASSAGEWAYS 


diameter.  By  the  third  year  the  diameter  has  increased  to  3  mm.  or  over, 
extremes  being  observed  from  1.5  mm.  to  6  mm.  The  latter  diameter 
is,  however,  very  unusual. 

A 


FIG.  1 70. — Photomicrographs  of  frontal  sections  through  the  nasolacrimal  passageways  of  a  human 
embryo  aged  128  days.  Note  the  solid  portions  of  the  lacrimal  ducts  in  Fig.  A.  In  Fig.  B,  we  have 
a  patent  section  (Is)  of  the  ocular  end  of  the  nasolacrimal  duct  and  in  Fig.  C,  a  section  of  the  mid-por- 
tion of  the  nasolacrimal  duct  still  solid  (nld).  Note  the  well  established  lumen  (nld)  at  the  nasal  end 
of  the  nasolacrimal  duct  in  Figs.  D  and  E.  "Note  how  extensive  the  contact  point  between  the  naso- 
lacrimal duct  and  the  inferior  nasal  meatus  will  be  (Fig.  D). 

Sid  =  superior  lacrimal  duct;  ild  =  inferior  lacrimal  duct;  Is  =  lacrimal  sac;  nld  =  nasolacrimal 
duct;  inc  =  inferior  nasal  concha;  inm  =  inferior  nasal  meatus.  X  19.  (After  J.  P.  S.) 

The  lacrimal  sac  and  the  nasolacrimal  duct  are  relatively  fixed  from 
the  onset  as  far  as  position  is  concerned.  The  paranasal  (accessory) 
sinuses  are,  therefore,  not  as  intimately  related  to  the  nasolacrimal  pas- 


DEVELOPMENT 


241 


sageways  as  later  when  the  sinuses  assume  larger  dimensions.  Despite 
the  general  truth  of  the  foregoing,  the  maxillary  sinus  and  the  nasolacrimal 
duct  bear  important  and  fairly  close  anatomic  relationships  even  before 
birth.  At  birth  the  nasolacrimal  duct  lies  on  the  average  but  2  mm. 


FIG.  171. — Photomicrographs  of  sections  through  the  nasolacrimal  duct.  A,  from  a  child  at  term. 
Note  that  the  barrier  (lacrimonasal  membrane)  between  the  nasolacrimal  duct  and  the  inferior  nasal 
meatus  is  still  intact.  X  3.4.  B,  from  a  7-month  fetus,  the  lacrimonasal  membrane  intact.  X  6. 
C,  from  a  term  child,  the  lacrimonasal  membrane  markedly  thinned  out  but  unruptured.  Particu- 
larly note  the  irregularity  of  the  nasolacrimal  duct.  D,  from  an  adult,  aged  60  years.  E,  from  an 
adult,  aged  65  years.  Note  the  diverticulum  (X).  X  2.6.  F,  from  an  adult,  aged  70  years.  In 
the  region  of  the  ostium  of  the  common  lacrimal  duct. 

directly  in  front  of,  or  from  1.5  mm.  to  2  mm.  medial  to  the  ventral  end  of 
the  maxillary  sinus.     By  the  eighteenth  month  the  distance  intervening 


242  THE  NASOLACRIMAL  PASSAGEWAYS 

between  the  maxillary  sinus  and  the  nasolacrimal  duct  is  reduced  for  a 
limited  segment  of  the  duct  to  an  intimacy  not  unlike  in  the  adult.  Of 
course,  only  later,  when  the  infraorbital  recess  assumes  goodly  proportions, 
is  the  nasolacrimal  duct  exposed  to  the  surface  of  the  maxillary  sinus 
for  a  considerable  distance. 

Of  the  ethmoidal  cells,  those  developing  from  the  frontal  recess  of 
the  middle  nasal  meatus  are  nearest  the  lacrimal  sac  at  birth.  However, 
the  anatomic  relationship  is  not  intimate  at  this  time.  Indeed,  in  a 
child  aged  from  18  to  24  months  from  5  to  7  mm.  usually 
intervene  between  the  lacrimal  sac  and  the  nearest  ethmoidal  cell  (Fig. 
151).  Rarely  a  more  precocious  ethmoidal  cell  establishes  very  intimate 
anatomic  relations  with  the  sac  at  an  earlier  period  of  extrauterine  life. 

By  the  sixth  year  the  maxillary  sinus  establishes  fairly  intimate 
relationships  with  the  upper  portion  of  the  nasolacrimal  duct,  and  the 
frontal  ethmoidal  cells  have  pneumatized  the  region  formerly  existing 
between  the  lacrimal  sac  and  the  frontal  recess.  Infundibular  cells  like- 
wise not  infrequently  early  seek  lacrimal  sac  relations.  Indeed,  the  rudi- 
mentary frontal  sinus  (either  frontal  recess  or  frontal  ethmoidal  cell, 
see  page  143)  must  be  thought  of  in  the  early  relationships  of  the  lac- 
rimal sac. 

After  the  eleventh  year  the  anatomic  relationships  between  the  para- 
nasal  sinuses  and  the  nasolacrimal  passageways  are  essentially  those  of 
the  adult  (Fig.  153). 

Variations  and  Anomalies. — The  variations  and  anomalies  in  the 
nasolacrimal  passageways  as  encountered  in  postfetal  life  are  readily 
accounted  for  by  the  potentialities  of  development  of  the  anlage  of  the 
duct  system.  Double  and  triple  lacrimal  pun  eta  and  lacrimal  ducts  have 
been  observed  by  the  author.  Indeed,  Majewski  found  a  case  of  quad- 
ruple puncta.  Should  the  cephalic  end  of  the  solid  epithelial  cord  give 
rise  to  more  than  two  lacrimal  sprouts,  the  usual  number,  either  the  upper 
or  the  lower  eyelid  or  both  might  have  multiple  lacrimal  ducts  and  puncta. 
Some  of  the  multiple  outgrowths  fail,  however,  at  times  to  reach  the  free 
border  of  the  eyelid.  Moreover,  should  one  or  the  other  of  the  two  usual 
lacrimal  sprouts  fail  to  reach  the  free  border  of  the  eyelid  there  would, 
of  course,  be  an  absent  lacrimal  duct  and  papilla;  or  should,  perchance, 
the  solid  lacrimal  sprout  after  reaching  the  free  border  of  the  eyelid  fail 
to  become  canalized  at  that  point,  a  lacrimal  papilla  with  an  absent  lacri- 
mal punctum  would  result.  It  does  not  necessarily  follow  that  multiple 
puncta  mean  a  corresponding  number  of  lacrimal  ducts;  an  extensive 
coalescence  of  a  single  lacrimal  duct  with  the  free  border  of  the  eyelid 


VARIATIONS  AND  ANOMALIES  243 

may  establish  multiple  ostia  or  puncta.  Again,  a  lacrimal  punctum  may 
be  represented  by  a  slit-like  furrow  along  the  edge  of  the  eyelid. 

Congenital  fistula  of  the  lacrimal  sac  is  occasionally  encountered 
as  a  unilateral  or  bilateral  defect.  It  usually  means  an  arrested  develop- 
ment in  the  obliteration  of  the  optical  end  of  the  naso-optic  furrow .  At 
times  it  would  seem  that  the  defect  is  due  to  an  attenuation  of  a  diverticu- 
lum  of  the  lacrimal  sac. 

Auxiliary  lateral  buddings  of  the  solid  or  uncanalized  nasolacrimal 
duct  are  very  common  at  one  stage  of  the  human  embryo  (Fig.  172). 
Apparently,  many  of  these  suffer  early  absorption.  However,  a  study 


fossa.  nascJis 


Oculus 

«e 

7iMsolacrima2is 


Conditx.  nasatis  inferior 

2  3 

FIG.  172. — In  No.  i  are  shown  outlines  of  the  lumen  of  the  ductus  nasolacrimalis  at  various  levels. 
What  appears  to  be  two  ductus  nasolacrimales  lying  side  by  side  at  one  level  turns  out  to  be  the 
main  duct  and  a  diverticulum  from  it.  Prom  an  adult.  (After  J .  P.  S.) 

In  No.  2  is  illustrated  a  frontal  section  through  the  nasal  fossa  of  a  forty-day  human  embryo. 
The  advanced  rudiment  of  the  nasolacrimal  passageways  is  indicated  in  solid  black.  Note  the  com- 
plete isolation  from  the  surface  and  the  lacrimal  ducts  sprouting  from  the  main  cord  of  cells.  Lateral 
auxiliary  buds,  the  rudiments  of  diverticula,  are  shown  protruding  from  the  main  cord  of  cells.  (After 
J.  P.  S.) 

In  No.  3  is  shown  the  irregular  canalization  of  the  ductus  nasolacrimalis.  From  a  child  aged  one 
day.  (After  J.  P.  S.) 

of  much  embryologic  and  adult  material  has  convinced  the  author  that 
the  very  common  diverticula  of  the  adult  nasolacrimal  duct  have  their 
origin  in  these  embryonic  lateral  buddings.  As  the  main  duct  becomes 
canalized  the  process  is  carried  into  the  auxiliary  buds  in  the  formation 
of  diverticula.  Indeed,  the  case  described  by  Geddes1  in  which  the  naso- 
lacrimal duct  communicated  with  the  middle  nasal  meatus  can  be  ex- 
plained by  such  a  lateral  bud.  These  diverticula  always  communicate 

1  An  Abnormal  Nasal  Duct,  Anatom.  Anz.,  Bd.  37,  No.  i,  1910. 


244  THE  NASOLACRIMAL  PASSAGEWAYS 

with  the  main  nasolacrimal  duct  and  are  lined  by  an  epithelium  not  un- 
like that  of  the  main  duct  (see  page  250).* 

The  connections  of  the  uncanalized  nasolacrimal  duct  with  the  epithe- 
lium of  the  inferior  nasal  meatus  occurs  at  various  levels.  At  times  the 
coalescence  takes  place  at  the  highest  point  or  cupola  of  the  inferior  nasal 
meatus.  Again,  it  may  occur  at  any  point  on  the  lateral  wall  of  the  in- 
ferior meatus  in  the  plane  of  the  duct.  In  the  canalization  of  the  field  of 
union  between  the  nasolacrimal  duct  and  the  inferior  nasal  meatus  from 
one  to  three  ostia  are  established.  The  single  ostium  is,  of  course,  the 
more  usual.  The  attenuation  and  rupture  of  the  membranous  septum, 
composed  of  two  layers  of  abutting  epithelium  with  a  limited  amount  of 
intervening  connective  tissue,  located  between  the  lumen  of  the  naso- 
lacrimal duct  and  the  inferior  nasal  meatus,  is  not  unlike  the  rupture 
of  the  bucconasal  membrane  in  the  establishment  of  the  connection  be- 
tween the  primitive  nasal  fossa  and  the  primitive  buccal  cavity.  Should 
the  membranous  barrier  between  the  inferior  nasal  meatus  and  the  naso- 
lacrimal duct  fail  of  canalization  or  rupture,  atresia  of  the  nasolacrimal 
duct  would,  of  course,  result.  The  author  has  encountered  atresias  in 
many  newborn  babies  and  a  few  in  children  that  died  during  the  first 
year  of  infancy.2  Doubtless  the  atresia  in  the  newborn  of  the  naso- 
lacrimal duct  due  to  a  persistent  lacrimonasal  membrane  is  in  many  in- 
stances short-lived — the  already  thin  membrane  soon  suffering  "  rupture." 
Occasionally,  however,  surgical  intervention  is  necessary  (Fig.  172). 

The  Lacrimal  Fossa  and  the  Nasolacrimal  Canal. — Before  considering 
the  membranous  lacrimal  ducts  and  sac  and  the  nasolacrimal  duct  it  is 
well  that  one  has  a  clear  conception  of  the  osseous  relations.  The  fossa 
of  the  lacrimal  sac  (fossa  sacci  lacrimalis)  is  an  oblong  rounded  depression 
or  sulcus  located  on  the  ventromedial  aspect  of  the  orbit,  the  frontal 
process  of  the  maxilla  and  the  lacrimal  bone  participating  more  or  less 
equally  in  its  formation.  The  fossa  is  limited  dorsally  by  the  prominent 
posterior  lacrimal  crista  (crista  lacrimalis  posterior)  and  ventrally  by  the 
anterior  lacrimal  crista  (crista  lacrimalis  anterior),  the  former  a  crest 
on  the  lacrimal  bone  and  the  latter  a  crest  on  the  frontal  process  of  the 
maxilla.  Cranialward  the  lacrimal  fossa  becomes  shallower  and  shallower, 
ultimately  losing  its  identity  at  the  fronto-lacrimo-maxillary  suture  line, 

1  J.  Parsons  Schaeffer:  Nasolacrimal  Duct  Diverticula  and  Their  Genetic  Significance,  The  Anat. 
Rec.,  Vol.  9,  1915. 

2  For  a  more  detailed  account  of  the  embryology  and  development  of  the  nasolacrimal  passage- 
ways in  man,  the  reader  is  referred  to  a  previous  study  with  an  appended  bibliography.     J.  Parsons 
Schaeffer:  The  Genesis  and  Development  of  the  Nasolacrimal  Passages  in  Man,  Amer.  Jour.  Anat., 
Vol.  13,  1912. 


OSSEOUS  NASOLACRIMAL  CANAL 


245 


while  nasalward  the  fossa  is  directly   confluent  with  the  osseous  naso- 
lacrimal  canal  (Fig.  145). 

The  osseous  nasolacrimal  canal,  the  direct  continuation  of  the  lacrimal 
sulcus  or  fossa,  is  formed  by  the  maxilla,  the  lacrimal  bone  and  the  inferior 
nasal  concha  or  turbinated  bone,  the  maxilla  by  its  frontal  process  and 
body  contributing  the  greater  portion  of  the  boundaries.  Rarely  the 


Sinus  frontales - 

Saccus  lacriincdis 

Ductns  lacrhnalcs _. 

Ductus  nasolacrimalis 

Ostfuni  na.sola.crimal(i , 


Sinus  Tttaxilltxrii ___ 

Heoitus  nasi  inferior. 

Concha  nasalis  inferior.. -- 
Ductus  nasolacrimulis  — 
Sinus  maxillaris , 


FIG.  173. — A  dissection  showing  the  nasolacrimal  passageways  and  the  relations  of  the  nasolac- 
rimal duct  to  the  maxillary  sinus  and  the  inferior  nasal  meatus.  The  inset  is  a  transection  of  the 
nasal  fossae,  the  maxillary  sinuses,  and  the  nasolacrimal  ducts. 

lacrimal  bone  fails  to  participate  in  the  formation  of  the  osseous  naso- 
lacrimal canal,  being  replaced  by  an  extension  of  the  frontal  bone  or  the 
maxilla.  The  canal  terminates  immediately  below  the  attached  border 
of  the  inferior  nasal  concha  on  the  lateral  wall  and  cupola  of  the  inferior 
nasal  meatus  in  a  wide-mouthed  ostium.  The  length  of  the  osseous 
nasolacrimal  canal  does  not  necessarily  conform  to  the  enclosed  mem- 


246  THE  NASOLACRIMAL  PASSAGEWAYS 

branous  nasolacrimal  duct,  which  is  frequently  longer  (vide  infra).  The 
osseous  canal  proper  varies  in  length  from  10  to  20  mm.  and  the  lacrimal 
sulcus  or  fossa  from  10  to  14  mm.,  making  a  total  length  of  the  osseous 
channels  from  20  to  34  mm.  The  diameter  of  the  osseous  canal  measures 
from  4  to  7  mm. ;  however,  is  seldom  uniform  throughout. 

The  plane  of  direction  of  the  osseous  nasolacrimal  canal  must  obvi- 
ously conform  to  the  type  of  the  facial  skeleton.  Moreover,  the  breadth 
of  the  bridge  of  the  nose,  the  degree  of  expansion  of  the  pyriform  aperture, 
and  the  width  of  the  inferior  nasal  meatus  are  extremely  variable  and 
necessarily  influence  the  course  of  the  nasolacrimal  canal  and  its  contained 
membranous  duct.  In  a  general  way  one  may  say  that  the  direction  of 


Lacrl.ntcd 

protuberance . .  - 


Sinws 

FIG.  174. — A  dissection  showing  excessive  pneumatization  or  hollowing  out  of  the  maxilla  by  the 
maxillary  sinus.  All  of  the  recesses  of  the  sinus  are  extensively  developed;  the  lacrimal  protuberance 
prominent. 

the  osseous  nasolacrimal  canal  is  caudal  ward,  lateral  ward  and  dorsal- 
ward.  As  a  rule,  the  osseous  nasolacrimal  canal  is  illustrated  in  text-books 
as  coursing  in  an  almost  vertical  plane.  A  study  of  a  large  series  of  speci- 
mens has  convinced  the  author  that  the  true  plane  of  the  canal  is  seldom, 
if  ever,  vertical  in  the  exact  coronal  plane,  but  that  it  is  projected  in  a 
decidedly  oblique  plane  from  the  lacrimal  fossa  to  a  variable  point  on  the 
medial  aspect  of  the  alveolar  process  of  the  maxilla,  corresponding  to  the 
interval  between  either  the  second  premolar  and  the  first  molar,  the 
first  and  second  molars,  or  even  as  far  dorsally  as  the  interval  between 
the  second  and  third  molar  teeth. 

The  osseous  nasolacrimal  canal  courses  in  the  lateral  nasal  wall 
between  the  ventral  portion  of  the  middle  nasal  meatus  and  the  maxillary 


LACRIMAL  DUCTS 


247 


sinus,  conforming  more  or  less  closely  to  the  vertical  confines  of  the  middle 
meatus  (Fig.  197).  Not  infrequently  the  canal  throws  a  portion  of  the 
mesial  or  nasal  wall  of  the  maxillary  sinus  into  a  columnar  relief  (Figs.  102 
and  174).  The  thickness  of  bone  intervening  between  the  maxillary  sinus 
and  the  osseous  nasolacrimal  canal  varies  from  a  papery  thinness  to  2  or 
3  mm.  It  is  especially  thin  when  the  maxillary  sinus  develops  extensively 
into  the  frontal  process  of  the  maxilla  in  the  formation  of  the  infraorbital 
or  prelacrimal  recess.  Moreover,  the  nasolacrimal  canal  and  the  lacrimal 
fossa  come  into  intimate  relationship  with  certain  anterior  ethmoidal 
cells.  The  author  observed  also  a  number  of  instances  in  which  the 
frontal  sinus  in  addition  to  pneumatizing  into  the  nasal  bone  extended 
laterally  and  caudally  into  the  frontal  process  of  the  maxilla,  thereby 
establishing  most  intimate  relationships  with  the  lacrimal  fossa  and  its 
contained  lacrimal  sac. 

The  Lacrimal  Ducts  (ductus  lacrimales). — The  lacrimal  ducts  or 
canaliculi  begin  by  minute  openings,  the  lacrimal  puncta,  which  normally 
either  surmount  or  are  placed  on  the  sides  of  the  conical  lacrimal  papilla 
located  on  the  free  borders  of  the  eyelids,  the  upper  about  6  mm.  and 
the  lower  about  8  mm.  from  the  medial  palpebral  commissure  (internal 
canthus).  The  lacrimal  ducts  consist  of  vertical  and  horizontal  portions 
with  dilatations  or  ampullae  at  the  genua  or  bends.  The  ducts  average 
from  8  to  10  mm.  in  their  total  length;  o.i  to  0.2  mm.  in  diameter  at  the 
puncta,  i  mm.  at  the  genua  and  0.5  to  0.8  mm.  in  the  horizontal  portions. 
Irregularities  and  sacculations  are  not  uncommon  (Fig.  178).  The  in- 
ferior lacrimal  duct  is  almost  invariably  longer  than  the  superior  duct,  with 
its  punctum  and  papilla  farthest  removed  from  the  medial  palpebral 
commissure. 

Each  lacrimal  duct  has  a  lining  of  stratified  squamous  epithelium 
resting  upon  a  sparse  tunica  propria  rich  in  elastic  fibers.  The  orbicularis 
palpebrarum  muscle  strengthens  the  ducts.  Some  of  these  muscle  fibers 
parallel  the  horizontal  limbs  and  others  encircle  sphincter-like  the  vertical 
limbs  of  the  ducts. 

The  horizontal  portions  of  the  lacrimal  ducts  communicate  with  the 
lacrimal  sac  in  varying  ways :  (a)  the  ducts  may  unite  into  a  short,  narrow 
common  duct  and  this  in  turn  establish  communication  between  the 
lacrimal  ducts  and  the  lacrimal  sac  (the  usual  way  of  communication); 
(b)  the  ducts  may  empty  separately  into  an  apparent  diverticulum  of  the 
lacrimal  sac — the  superior  sinus  (Maier)  of  the  lacrimal  sac  (this 
diverticulum  may,  however,  be  thought  of  as  a  wide  common  duct  of 
the  lacrimal  ducts) ;  (c)  the  ducts  rarely  empty  separately  into  the  lacrimal 


248 


THE  NASOLACRIMAL  PASSAGEWAYS 


sac,  i.e.,  there  is  neither  a  common  duct  nor  a  diverticulum  from  the 
lacrimal  sac.1 

The  distal  ends  of  the  lacrimal  ducts  do  not  bear  an  intimate  relation- 
ship to  the  nasal  fossa  or  the  paranasal  sinuses.  The  relations  of  the 
proximal  or  terminal  ends  of  the  ducts  are  essentially  those  of  the  lacrimal 
sac  which  will  be  discussed  in  subsequent  paragraphs. 

The  Lacrimal  Sac  (saccus  lacrimalis)  and  the  Nasolacrimal  Duct 
(ductus  nasolacrimalis). — The  membranous  lacrimal  sac  for  the  most 


Ductu,s  nasofrontalis . 

tfnfltndiL  of  frontal  sinus) 

ethirwidale 


J)vttn,s  nasdacrunaJUs 


Agger  nasi  ceil. ^\ 

(C.  et/tmoiotaZis  antj  V 
Recessus  prclacrimalis ,    ' 
(Sinv,s  mtudllaris)    \ 


Ttecesses  --''' 
(S.sphertoidaU*} 


FIG.  175. — A  dissection  of  the  lateral  nasal  wall  with  especial  reference  to  the  nasolacrimal  duct, 
the  lacrimal  sac  (indicated  by  dotted  outline,  in  white),  the  agger  nasL  cell,  and  the  prelacrimal  recess 
of  the  sinus  maxillaris. 

The  inset  is  a  transection  showing  the  relations  of  the  nasolacrimal  duct. 

Note  the  extension  of  the  sphenoidal  sinus  beneath  and  dorsal  to  the  hypophyseal  fossa  in  the 
large  figure. 

part  occupies  the  shallow  lacrimal  fossa,  extending,  however,  for  a  greater 
or  less  distance  into  the  upper  end  of  the  lacrimal  canal.  It  may  be 
considered  the  upper  dilated  extremity  of  the  nasolacrimal  duct  and  is 

1  J.  Parsons  Schaeffer:  Variations  in  the  Anatomy  of  the  Nasolacrimal  Passages,  Annals    of 
Surgery,  August,  1911. 


LACRIMAL  SAC  AND  NASOLACRIMAL  DUCT  249 

bridged  over  by  the  palpebral  fascia  which  extends  from  the  anterior  to 
the  posterior  lacrimal  crests.  Moreover,  it  is  covered  by  the  medial  palpe- 
bral ligament,  fibers  of  the  orbicularis  palpebrarum,  and  at  places  merely 
by  skin  and  subcutaneous  tela.  The  upper  rounded  extremity  or  fornix 
of  the  lacrimal  sac  is  located  at  varying  distances  above  the  medial  pal- 
pebral ligament.  On  the  dorsolateral  aspect  of  the  sac  where  the  medial 
palpebral  ligament  crosses  is  located  the  orifice  (or  orifices)  of  the  united 
lacrimal  ducts.  This  orifice  is  usually  located  from  2  to  5  mm.  from  the 
extreme  top  or  fornix  of  the  lacrimal  sac. 

As  a  rule,  the  lacrimal  sac  merges  imperceptibly  with  the  naso- 
lacrimal  duct,  save  for  a  slight  constriction — the  isthmus.  The  major 
portion  of  the  nasolacrimal  duct  is  entirely  encased  by  bone,  e.g.,  the 
nasolacrimal  canal.  In  many  instances  the  nasal  end  of  the  nasolacrimal 
duct  is  continued  for  a  considerable  distance  beyond  the  nasal  end  of  the 
osseous  nasolacrimal  canal  within  the  mucous  membrane  of  the  lateral 
wall  of  the  inferior  meatus.  This  extension  accounts  for  the  discrepancy 
in  length  between  the  osseous  nasolacrimal  canal  and  the  membranous 
nasolacrimal  duct;  moreover,  divides  the  latter  into  osseous  and  purely 
membranous  segments.  The  lacrimal  sac  measures  on  the  average  12  mm. 
in  its  vertical  plane  and  from  2  to  5  mm.  in  its  transverse.  Owing  to 
the  varied  location  of  the  nasolacrimal  ostium  in  the  inferior  meatus,  the 
length  of  the  nasolacrimal  duct  is  necessarily  inconstant,  varying  from 
10  to  28  mm.  The  diameter  of  the  nasolacrimal  duct  is  not  uniform, 
measuring  at  the  isthmus  or  point  of  transition  from  the  sac  to  the  duct 
but  3  mm.;  becoming  wider  below  this  point  it  averages  about  5  mm. 
in  its  ventrodorsal  diameter  and  4  mm.  in  its  transverse  diameter.  _ 

As  stated  above,  the  lacrimal  sac  and  the  nasolacrimal  duct  frequently 
merge  in  such  a  manner  that  the  limitations  of  the  sac  can  only  arbitrarily 
be  determined.  However,  not  infrequently  the  lacrimal  sac  is  very  much 
wider  than  the  nasolacrimal  duct  at  the  junction  point,  making  the  ex- 
tent of  the  sac  very  obvious.  Again,  the  lacrimal  sac  and  the  nasolacri- 
mal duct  instead  of  merging  in  a  linear  fashion  are  joined  side  to  side  in 
an  indirect  continuity,  the  fornix  of  the  nasolacrimal  duct  appearing  dome- 
like at  the  side  of  the  lacrimal  sac  (Fig.  178).  It  is,  of  course,  obvious  that 
it  is  utterly  impossible  in  the  latter  type  to  pass  a  lacrimal  probe  from  the 
lacrimal  sac  into  the  nasolacrimal  duct  wihout  making  artificial  openings 
by  the  advancing  probe.  On  the  other  hand,  the  lacrimal  probe  is  passed 
from  the  lacrimal  sac  into  the  nasolacrimal  duct  with  relative  ease  when 
they  are  in  direct  linear  continuity  (Fig.  180). 

The  fibro-elastic  walls  of  the  lacrimal  sac  partake  of  the  nature  of  a 


250 


THE  NASOLACRIMAL  PASSAGEWAYS 


lymphoid  tissue  and  are  connected  with  the  periosteum  by  a  loose  areolar 
stratum  containing  a  dense  plexus  of  small  veins.  These  anatomic  factors 
account  for  the  ready  and  marked  congestion  of  the  sac  following  trauma 
and  infection.  The  lacrimal  sac  is  lined  with  a  double  layer  of  columnar 
epithelial  cells,  some  of  which  are  ciliated.  Here  and  there  branched 
tubular  glands  are  encountered.  The  nasolacrimal  duct  likewise  is  fibro- 
elastic  and  separated  from  the  surrounding  periosteum  by  a  loose  tissue 
rich  in  veins.  It  is  lined  by  columnar  epithelial  cells.  Small  branched 
tubular  glands  are  found,  especially  as  the  duct  nears  its  nasal  termination. 
Nasolacrimal  Duct  Diverticula  and  Valves. — It  is  generally  believed 
that  the  walls  of  the  nasolacrimal  duct  are  always  regular  and  that  the 


Lateral  wall 


FIG.  176. — Photographs  of  transections  of  the  nasolacrimal  duct  at  the  point  of  communication 
with  the  inferior  nasal  meatus;  that  is,  at  the  level  of  the  ostium  nasolacrimale  (O).  The  sections 
are  from  adults  and  are  magnified  from  2  to  4  times.  (After  J.  P.  S.) 

lumen  of  the  duct  presents  a  more  or  less  uniform  cylindrical  outline.  In- 
deed, this  is  what  one  gathers  from  many  text-books  and  from  the  average 
gross  dissection  of  the  channel.  However,  serial  sections  of  the  duct  and 
reconstructions  of  its  lumen  at  once  show  the  fallacy  of  this  belief. 

Admittedly,  a  large  number  of  nasolacrimal  ducts  have  regular 
and  more  or  less  uniform  walls.  The  formation  of  valve-like  folds  by  the 
mucous  membrane  of  the  nasal  duct  in  the  upper  and  middle  thirds  has 
been  frequently  described.  Krause  and  Beraud  described  a  valve  at 
the  junction  of  the  lacrimal  sac  and  the  lacrimal  ducts.  Careful  study 
indicates  that  in  many  cases  the  so-called  valve  is  merely  a  simple  elevation 
of  mucous  membrane.  However,  the  mucous  membrane  may  be  suffi- 
ciently reduplicated  to  form  a  true  valve.  The  writer  agrees  with  Boch- 


NASOLACRIMAL  OSTIUM 


FIG.  177. — Drawings  of  actual  dissections  illustrating  various  types  of  ostia  nasolacrimalia  en- 
countered in  this  study.  The  reader  is  referred  to  the  text  for  a  further  consideration  of  them.  The 
concha  nasalis  inferior  is  partly  cut  away  so  as  to  expose  for  study  the  manner  of  communication 
between  the  ductus  nasolacrimalis  and  the  meatus  nasi  inferior. 


252 


THE  NASOLACRIMAL  PASSAGEWAYS 


dalek  that  the  opening  of  the  lacrimal  ducts  may  be  placed  in  the  center 
of  a  diaphragm-like  lamina  of  mucous  membrane.  Again,  one  encounters 
many  specimens  in  which  there  is  no  evidence  whatsoever  of  mucosal  pli- 
cae or  valves.  Additional  valves  have  been  described  for  the  mid-portion 
of  the  nasolacrimal  duct.  These  folds  of  mucous  membrane  are  usually 
of  minor  importance  and  may  occur  in  nasolacrimal  ducts  presenting 
regular  walls. 

Recent  investigations  by  the  author  indicate  that  many  nasolacrimal 
ducts  present  lumina  of  very  irregular  contour,  some  even  more  or  less 
tortuous  in  course.  Minor  irregularities,  as  stated  above,  are  at  times  due 
to  mere  folds  in  the  mucous  membrane.  In  many  instances  they  are  of 
little  moment.  Again,  they  may  form  definite  bridges  along  the  walls 
of  the  duct.  Entirely  apart  from  these  minor  irregularities,  diverticula 
or  direct  outpouchings  of  the  nasolacrimal  duct  are  not  uncommon. 
They  vary  from  those  of  insignificant  size  to  those  of  relatively  large 
dimensions.  In  studying  cross  sections  of  the  nasolacrimal  duct  one  is 
at  times  puzzled  to  explain  what  are  apparently  two  ducts  lying  side  by 
side.  However,  by  following  the  sections  serially  one  finds  that  one  cavity 
sooner  or  later  communicates  with  the  other,  e.g.,  one  turns  out  to  be  the 
nasolacrimal  duct  proper  and  the  other  a  diverticulum  from  it  (Fig.  172). 
These  diverticula  must  be  very  important  clinically  since  they  are  so 
located  that  they  readily  retain  infectious  material  within  their  confines. 
Indeed,  they  may  be  important  factors  in  the  chronicity  of  pathologic 
conditions  of  the  nasolacrimal  duct.  Owing  to  the  irregularity  of  the 
lumen  of  the  nasolacrimal  duct  and  the  presence  of  large  diverticula, 
it  is  obvious  that  false  passageways  are  repeatedly  made  by  operators 
when  they  pass  the  lacrimal  probe. 

The  diverticula  are  lined  with  a  mucous  membrane  similar  to  that 
lining  the  main  duct,  and  at  the  ostia  of  the  diverticula  the  mucous  mem- 
branes of  the  main  duct  and  diverticula  are  directly  continuous,  both 
grossly  and  histologically.  Genetically,  the  diverticula  are,  doubtless, 
the  result  of  canalization  of  auxiliary  lateral  buds  which  grow  from  the 
solid  cord  of  epithelial  cells  representing  the  rudiment  of  the  nasolacrimal 
passageways.  It  must,  therefore,  be  concluded  from  the  evidence  at 
hand  that  the  diverticula  from  the  nasolacrimal  duct  are  of  congenital 
origin  and  are  not  acquired  in  later  life.1 

The  Nasal  and  Paranasal  Relations  of  the  Membranous  Lacrimal 
Passageways. — The  relations  between  the  anterior  ethmoidal  cells  and 

1  J.  Parsons  Schaeffer:  Nasolacrimal  Duct  Diverticula  and  Their  Genetic  Significance,   The 
Anat.  Rec.,  Vol.  9,  1915. 


RELATIONS  OF  PASSAGEWAYS  253 

lacrimal  sac  are  more  or  less  variable.  Very  commonly,  however,  two 
or  more  anterior  ethmoidal  cells  (frontal  and  infundibular)  immediately 
adjoin  the  dorsal  and  medial  aspects  of  the  lacrimal  sac.  Indeed,  the 
osseous  walls  separating  the  mucous  membranes  of  the  ethmoidal  cells  and 
the  lacrimal  sac  very  frequently  under  normal  conditions  show  dehiscences. 
At  times  ethmoidal  cells  crowd  for  a  considerable  distance  forward  along 
the  lateral  border  and  over  the  cupola  of  the  lacrimal  sac.  Even  more 
common  is  the  extension  of  anterior  ethmoidal  cells  over  the  medial  or 
nasal  side  of  the  lacrimal  sac  and  the  beginning  of  the  nasolacrimal  duct. 
Cells  in  the  latter  position  usually  grow  from  the  infundibulum  ethmoidale 
(infundibular  cells).  However,  at  times  extensions  of  ethmoidal  cells 
from  the  frontal  recess  are  found  between  the  lacrimal  sac  and  the  middle 
nasal  meatus.  When  practising  endonasal  dacryocystotomy  these  cells 
must,  of  course,  first  be  ablated  before  the  osseous  walls  of  the  lacrimal 
sac  and  the  ocular  end  of  the  nasolacrimal  duct  can  be  reached  (Fig.  175). 
Two  lamina  of  bone  intervene  in  such  cases  between  the  nasal  fossa  and  the 
lacrimal  sac  and  duct.  Not  infrequently,  the  entire  wall  of  the  lacrimal 
fossa  is  pneumatized  by  ethmoidal  cells,  some  of  which  may  extend  for 
a  variable  distance  along  the  ocular  end  of  the  nasolacrimal  canal.  These 
cells  arise  variously  from  the  infundibulum  ethmoidale  and  the  frontal 
recess  and  extend  into  the  agger  nasi,  the  uncinate  process,  the  frontal 
process  of  the  maxilla  and  the  lacrimal  bone. 

The  nasolacrimal  duct  lies  adjacent  to  the  maxillary  sinus  and  very 
frequently  throws  into  relief  the  nasal  wall  of  the  sinus  in  the  form  of  a 
cord-like  swelling  which  corresponds  to  the  sinus  side  of  the  osseous  naso- 
lacrimal canal.  It  is  particularly  the  infraorbital  or  prelacrimal  recess 
of  the  maxillary  sinus  that  bears  the  most  intimate  relationship  to  the  naso- 
lacrimal duct  and  lacrimal  sac.  Unless  one  bears  this  extension  of  the 
maxillary  sinus  in  mind  in  endonasal  surgical  procedures,  the  maxillary 
sinus  is  readily  opened  into  instead  of  the  osseous  nasolacrimal  canal  and 
the  nasolacrimal  duct  (Fig.  175). 

As  stated  elsewhere,  the  frontal  sinus  usually  does  not  bear  an  inti- 
mate relationship  to  the  nasolac-imal  passageways.  When,  however,  the 
frontal  pneumatization  extends  into  the  nasal  bone,  the  frontal  process 
of  the  maxilla  and  the  lacrimal  bone  beyond  the  confines  of  the  suture 
line  separating  them  from  the  frontal  bone,  the  frontal  sinus  will  bear  a 
direct  relationship  to  the  lacrimal  fossa  with  its  contained  lacrimal  sac. 

The  Nasolacrimal  Ostium  (ostium  nasolacrimalis). — The  ostium  of 
the  nasolacrimal  duct  is  located  from  15  to  20  mm.  dorsal  to  the  limen  nasi 
and  from  30  to  40  mm.  from  the  nares  (anterior  nares).  It  is  frequently 


254 


THE  NASOLACRIMAL  PASSAGEWAYS 


found  at  the  most  cephalic  point  of  the  inferior  nasal  meatus,  that  is, 
immediately  caudal  to  the  point  of  attachment  of  the  inferior  nasal  concha 
to  the  lateral  nasal  wall.  When  in  this  position,  the  nasolacrimal  ostium 
usually  presents  a  wide  open  mouth  owing  to  the  osseous  supporting  ring. 
However,  it  is  equally  common  that  the  ostium  of  the  nasolacrimal  duct 
is  located  relatively  far  below  the  attached  point  of  the  inferior  concha, 
the  distance  varying  from  o  to  10  mm.  Between  these  two  extremes  one 
encounters  ostia  at  various  distances  caudal  to  the  attached  border  of  the 
inferior  nasal  concha. 

The  nasolacrimal  ostium  is  usually  a  single  opening.  However, 
duplicate  and  triplicate  communications  between  the  inferior  nasal  meatus 
and  the  nasolacrimal  duct  are  not  infrequently  met  with.  A  study  ot 
a  large  series  of  specimens  convinces  the  observer  that  there  is  no  unvary- 
ing typical  form  of  ostium,  but  that  several  normal  anatomic  types  are 
equally  common.  Indeed,  it  cannot  be  gainsaid  that  the  notion  of  an 
ideal  typical  form  must  be  abandoned  more  or  less  generally  and  in  its 
place  substituted  the  belief  and  knowledge  of  normal  anatomic  types. 
A  reference  to  Fig.  177,  in  which  are  represented  actual  delineations  of 
human  nasolacrimal  ostia,  will  indicate  a  number  of  the  fundamental 
anatomic  types  that  are  encountered.  The  belief  that  all  nasolacrimal 
ostia  are  provided  with  a  mucosal  valve  (plica  lacrimalis)  or  the  so-called 
valve  of  Hasner  must  be  abandoned.  When  the  nasolacrimal  duct  termi- 
nates immediately  caudal  to  the  attached  border  of  the  inferior  nasal 
concha,  its  ostium  almost  invariably  stands  permanently  open,  wide- 
mouthed  and  unguarded  by  a  valve-like  structure  (see  Nos.  i,  3,  6  in 
Fig.  177).  In  the  type  in  which  the  nasolacrimal  duct  passes  through  the 
nasal  mucous  membrane  rather  obliquely,  the  ostium  is  slit-like  and  in  a 
sense  merely  potential.  In  these  cases  the  ostium  may  be  said  to  be 
guarded  by  a  fold  of  mucous  membrane,  that  is,  a  plica  lacrimalis  of  Hasner 
(Fig.  177,  Nos.  5,  10).  Occasionally  the  nasal  end  of  the  nasolacrimal 
duct  pushes  nipple-like  into  the  inferior  nasal  meatus ;  surmounting  the 
nipple  is  located  the  nasolacrimal  ostium  (Fig.  177,  No.  7).  At  times  the 
nasolacrimal  ostium  proper  is  more  or  less  open  and  somewhat  guarded 
by  a  plica  lacrimalis.  Extending  from  the  ostium  toward  the  floor  of 
the  nose  is  a  fairly  deep,  gutter-like  groove  which  tends  to  become  deeper 
and  deeper  as  one  approaches  its  caudal  limits  (Fig.  177,  No.  9).  In  the 
type  of  ostium  shown  in  No.  5  of  Fig.  177  the  slit-like  aperture  becomes 
shallower  and  shallower  as  its  caudal  limits  are  reached  and  is  in  this 
respect  unlike  No.  9. 

The  nasolacrimal  ostium  is  at  times  exceedingly  small  (Fig.  177,  Nos. 


CONCLUDING  REMARKS 


255 


4,  10,  n)  and  wholly  inadequate  as  an  efficient  drainage  orifice.  These 
stand  in  marked  contrast  to  the  large  and  ever  open  ostia  shown  in 
Nos.  i,  3,  6  of  Fig.  177.  It  is  the  latter  ostia  that  are  so  easily  located 
and  probed  from  the  nasal  end  of  the  nasolacrimal  duct  and  that  escape 
collapse  from  enlargement  of  the  inferior  nasal  concha.  On  the  other 
hand,  it  is  the  slit-like  type  of  ostium  located  in  the  lateral  wall  of  the 
inferior  nasal  meatus  that  are  located  and  probed  with  difficulty  and 
readily  compressed  by  enlargement  of  the  inferior  nasal  concha,  occluded 
by  hypertrophy  or  congestion  of  the  mucous  membrane.  Indeed,  in  those 
cases  of  persistent  nasolacrimal  infection  despite  treatment  the  type  of 
nasolacrimal  ostium  may  be  an  important  factor  in  the  chronicity  of  the 
ailment. 

Concluding  Remarks. — Not  to  minimize  the  important  connections, 
both  anatomically  and  in  disease,  between  the  conjunctival  culdesac 
and  the  nasolacrimal  passageways,  the  etiological  connections  between 
disease  of  the  latter  and  the  nasal  fossa  and  paranasal  sinuses  are  generally 
recognized  as  of  paramount  importance.  This  is  in  comformity  with  the 
very  intimate  anatomic  relationships  that  exist.  At  best  but  papery 
laminae  of  bone  intervene  between  the  ethmoidal  labyrinth  and  the  orbit 
and  between  the  ventral  portion  of  the  ethmoidal  labyrinth  and  the 
lacrimal  sac  and  the  nasolacrimal  duct.  This  is  also^equally  true  of  the 
maxillary  sinus  in  many  instances.  Indeed,  congenital  dehiscences  in 
the  bony ' '  party- walls ' '  are  extremely  commonplace.  Moreover,  the  abun- 
dant network  of  lymphatic  vessels  are  vitally  important  in  establishing 
relations  between  the  mucous  membranes  of  the  nasal  and  the  nasolacrimal 
fields.  Again,  the  dense  venous  plexuses  of  the  nasal  mucous  membrane 
establish  connections  with  the  venous  plexuses  of  the  paranasal  sinuses 
and  those  surrounding  the  lacrimal  sac  and  the  nasolacrimal  duct.  The 
venous  plexuses  of  the  nasolacrimal  passageways  connect  also  with  the 
facial,  infraorbital  and  ophthalmic  veins;  and  as  Zuckerkandl  has  shown, 
a  lacrimo-facial  vein  connects  with  a  larger  vein  emerging  from  the  region 
of  the  anterior  ethmoidal  cells  and  passing  through  the  lacrimal  bone. 
These  anatomic  features  must  be  of  the  greatest  importance  in  the  spread 
or  extension  of  disease  from  the  nasal  fossa  and  the  related  paranasal 
sinuses  to  the  lacrimal  sac  and  the  nasolacrimal  duct  and  vice  versa. 

The  direct  communication  of  the  nasolacrimal  duct  with  the  inferior 
nasal  meatus  and  the  direct  continuity  of  the  mucous  membranes  through 
the  ostium  nasolacrimale  is  of  equally  great  importance  in  this  connection. 
The  ostium  is  frequently  very  large,  from  5  to  7  mm.  in  diameter,  standing 
permanently  open,  thereby  inviting  infection  from  the  nasal  fossa.  Again, 


256 


THE  NASOLACRIMAL  PASSAGEWAYS 


the  ostium  may  be  so  small  that  adequate  drainage  of  the  duct  is  utterly 
impossible,  or  the  ostium  if  located  in  the  mucous  membrane  of  the  in- 
ferior nasal  meatus  may  be  readily  encroached  upon  and  shut  off  by 
pathologic  nasal  states.  In  the  nasolacrimal  ostia  which  are  permanently 
open  and  unguarded  by  true  mucosal  valves,  air  and  fluids  readily  find 
their  way  into  the  nasolacrimal  duct.  It  has  been  shown  that  during 


FIG.   178.  FIG.   179. 

FIGS.  178  and  179. — Reconstruction  of  the  nasolacrimal  passageways  of  an  adult  aged  65  years. 
Fig.  178  represents  a  medial  view  and  Fig.  179  a  lateral  view  of  the  model.  Especially  note  the 
irregularity  and  the  diverticula  of  the  nasolacrimal  duct. 

The  inset  accompanying  Fig.  178  shows  the  details  of  the  side  to  side  union  of  the  lacrimal  sac 
and  the  nasolacrimal  duct;  moreover,  illustrates  the  large  bud-like  diverticulum  from  the  nasolacrimal 
duct.  X  3.2. 

SI  =  Saccus  lacrimalis;  Dls  =  Ductus  lacrimalis  superior;  Dli  =  Ductus  lacrimalis  inferior; 
Adi  =  Ampulla  ductus  lacrimalis;  Dlv  =  Ductus  lacrimalis  verticalis;  Dlh  =  Ductus  lacrimalis 
horizontalis;  Die  =  Ductus  lacrimalis  communis;  Dnl  =  Ductus  nasolacrimalis;  Mni  =  Meatus 
nasi  inferior;  Div'lm  =  Diverticulum  of  the  nasolacrimal  duct;  Jc  =  Junction  channel  between  the 
lacrimal  sac  and  the  nasolacrimal  duct. 

violent  blowing  of  the  nose  particles  of  secretion  are  forced  upward 
through  the  nasolacrimal  duct  into  the  lacrimal  sac.  Aubaret  observed 
the  ascent  of  very  minute  particles  of  tobacco-snuff  as  far  as  the  lacrimal 
puncta. 


CONCLUDING  REMARKS 


257 


In  some  cases  true  and  efficient  mucous-membrane  valves  guard 
the  nasal  end  of  the  nasolacrimal  duct.  It  would  appear  in  such  cases 
that  the  nasolacrimal  passageways  would  be  safeguarded  in  large  measure 
from  the  passage  of  infectious-laden  fluids  and  air  into  them  from  the 
inferior  nasal  meatus,  particularly  in  violent  blowing  of  the  nose  (Fig.  177). 

Other  factors  being  equal,  it 
would  seem  from  an  anatomic  view- 
point that  an  infected  nasolacrimal 
duct  and  lacrimal  sac  would  yield 
most  readily  to  treatment  in  those 
cases  in  which  the  nasolacrimal 
ostium  is  large,  permanently  open- 
mouthed  and  unobstructed  by  ana- 
tomic conditions  of  the  inferior 
meatus;  moreover,  in  which  the 
nasolacrimal  duct  is  free  of  mucosal 
ledges  and  diverticula.  On  the  other 
hand,  one  would  expect  infected 
nasolacrimal  passageways  to  resist 
treatment  and  the  ailment  to  enter 
the  stage  of  chronicity  in  those 
anatomic  types  in  which  the  naso- 
lacrimal duct  contains  diverticula 
(often  without  gravity  drainage), 
and  nasolacrimal  ostia  of  small  and 
inadequate  size  for  efficient  drainage; 
moreover,  a  nasal  ostium  or  aperture 
so  located  that  it  is  readily  in- 
fluenced by  conditions  of  the  inferior 
nasal  meatus.  The  success  or  failure 
of  non-surgical  treatment  of  the  diseased 
nasolacrimal  passageways  is  largely 


PIG.   1 80. — Reconstruction  of  the  nasolacri- 
mal  passageways   of   an   adult   aged  60  years. 
Note  the  regularity  of  the  nasolacrimal  duct  and 
7,7  ,7  t         '      4    ^         f    the  gradual  mergence  of  the  lacrimal  sac  into  the 

dependent  upon  the  anatomic  type  of  nas*lacrimai  duct  at  the  constriction  or  isth- 
nasolacrimal    duct    and    ostium    en-   mus-    x  3-2- 

,          .  Abbreviations  as  in  Figs.  178  and  179. 

countered.     Indeed,  here  as  elsewhere 

in  the  body  the  "anatomic  type"  looms  up  before  the  physician  as  an 

important  factor  in  treatment  and  prognosis. 

If  one  can  be  guided  by  clinical  reports  much  success  has  attended  the 
endonasal  operations  upon  the  nasolacrimal  duct  and  lacrimal  sac  when 
the  caudal  portion  of  the  duct  is  stenosed  or  its  ostium  of  communication 


258  THE  NASOLACRIMAL  PASSAGEWAYS 

with  the  inferior  meatus  is  blocked  by  pathologic  states  or  is  normally 
of  inadequate  size.  Toti's  endonasal  operation  on  the  lacrimal  sac  and 
West's  endonasal  window  resection  of  the  nasolacrimal  duct  cephalic 
to  the  inferior  nasal  concha  are  now  frequently  practised.  Moreover, 
new  operations  or  modifications  of  those  of  Toti  and  West  have  been 
devised,  particularly  by  Halle,  Polyak,  Mosher,  Green,  Wiener,  Yankauer, 
Beck,  etc.  The  nasolacrimal  duct  has  also  been  operated  upon  through 
the  maxillary  sinus — the  v.  Eicken's  operation.  Exonasal  operation, 
on  the  lacrimal  sac  are  also  frequently  practised.  Probing  of  the  naso- 
lacrimal passageways  would  seem  ill-advised  from  an  anatomic  viewpoint 
owing  to  the  very  common  irregularities  and  diverticula  of  the  nasolacrimal 
duct,  and  the  occasional  side  to  side  union  of  the  lacrimal  sac  and  the 
nasolacrimal  duct.  These  anatomic  conditions  preclude  the  successful 
passing  of  the  lacrimal  probe  in  very  many  instances.  The  advancing 
probe  doubtless  leaves  the  lumen  of  the  sac  or  duct  either  to  re-enter  the 
more  caudal  portion  of  the  duct  or  to  course  between  the  membranous 
duct  and  the  osseous  canal.  This  leads  to  artificial  openings  and  passage- 
ways and  leaves  the  patient  in  a  worse  state  than  before.  The  successful 
cases  are  doubtless  those  in  which  the  lacrimal  sac  merges  gradually  with 
the  nasolacrimal  duct  and  the  latter  is  fairly  regular  in  contour.  Un- 
fortunately there  is  no  way  of  knowing  what  type  of  duct  confronts  the 
operator. 


VHI-THE  NASAL  MUCOUS  MEMBRANE 


CHAPTER  VIII 
THE  NASAL  MUCOUS  MEMBRANE 

Conforming  with  the  anatomy  of  the  nasal  cavity  and  its  appendages 
the  lining  mucous  membrane  is  divided  into  three  more  or  less  distinct 
regions,  e.g.,  that  of  the  vestibule,  the  nasal  fossa,  and  the  paranasal  sinu- 
ses. Moreover,  the  structure  of  the  mucous  membrane  of  the  several 
regions  presents  characteristics  common  to  the  respective  fields.  In  ad- 
dition, the  mucous  membrane  of  the  nasal  fossa  is  histologically  divided 
into  two  unlike  portions,  conforming  thereby  to  the  physiology  of  the 
individual  parts. 

THE  NASAL  VESTIBULE 

As  a  sort  of  an  antechamber  to  the  nasal  fossa  we  have  the  nasal 
vestibule  which  corresponds  very  closely  in  its  extent  to  the  cartilaginous 
nasal  wall.  Its  lining  mucosa  is  often  referred  to  as  the  regio  vestibularis 
of  the  nasal  mucous  membrane.  At  the  naris  (nostril)  the  skin  of  the 
upper  lip  and  the  wing  of  the  nose  passes  into  the  vestibule  and  for  a 
distance  retains  its  surface  characteristics  of  a  stratified  flat  epithelium 
with  superficial  horny  cells.  The  skin  characters,  however,  are  lost  about 
the  middle  of  the  vestibule,  changing  here  to  stratified  flat  epithelium 
writh  an  absent  horny  layer,  resting  on  an  underlying  connective-tissue 
propria.  The  epithelium  of  the  forepart  of  the  vestibule  rests  on  a  con- 
nective-tissue corium  contihuous  with  that  of  the  skin.  The  fibrous  tunica 
propria  is  richly  provided  with  elastic  fibrils,  coarse,  stiff  hairs  (vibrissae), 
and  sebaceous  and  sudoriferous  glands.  In  the  deeper  part  of  the  ves- 
tibule the  connective-tissue  propria  contains  mixed  sere-mucous  glands 
which  replace  the  sweat  glands. 

THE  NASAL  FOSSA 

Conforming  with  the  double  function  of  the  nasal  cavity  proper  there 
are  two  areas  of  the  lining  mucous  membrane  (Schneiderian  or  pituitary 
membrane)  that  differ  in  structure—  the  pars  r&spiratoria  and  the  pars 
olfactoria.  The  latter  occupies  a  small  portion  of  each  nasal  fossa,  being 
confined  to  the  cephalic  third  of  the  nasal  septum,  nearly  the  whole  of  the 
superior  concha,  a  very  small  portion  of  the  middle  concha,  and  to  the 

261 


262  THE  NASAL  MUCOUS  MEMBRANE 

extreme  ventral  extremity  of  the  supernumerary  ethmoidal  concha  that 
may  exist  cephalic  to  the  superior  concha.  This  delineation  of  the  olfac- 
tory area  is  in  close  agreement  with  the  extended  researches  of  Read 
(Figs.  195  and  196),  but  is  more  extensive  than  the  long-accepted  olfactory 
area  (about  250  sq.  mm.)  of  Briinn.  The  remaining  portion  of  the  mucous 
membrane  is  devoid  of  olfactory  elements  and  is,  therefore,  classed  as 
respiratory. 

The  Respiratory  Portion  (pars  respiratoria). — The  stratiform  flat 
epithelium  of  the  nasal  vestibule  gradually  assumes  the  characteristics 
of  the  respiratory  mucous  membrane,  e.g.,  a  stratiform  ciliated  cylindrical 
epithelium.  This  transition  in  epithelium  takes  place  laterally  at  the 
limen  nasi  (vestibuli),  medially  at  the  septal  tubercle,  and  caudally  (floor) 
somewhat  dorsal  to  the  above  planes.  Individual  variations  as  to  the 
exact  place  of  the  transition  are  encountered. 

The  nasal  respiratory  mucous  membrane  varies  greatly  in  thickness 
in  the  several  parts  of  the  nasal  fossa.  Over  the  inferior  concha,  portions 
of  the  middle  concha,  and  adjacent  portions  of  the  septum  the  membrane 
frequently  reaches  a  thickness  of  several  millimeters ;  elsewhere  it  may  be 
considerably  less  than  a  millimeter.  The  thickness  of  the  mucous  mem- 
brane over  the  inferior  and  middle  conchas,  etc.,  is  largely  dependent  upon 
the  degree  of  development  within  the  tunica  propria  of  the  contained 
cavernous  tissue  (vide  infra).  Moreover,  the  membrane  is  intimately 
attached  to  the  periosteum  and  the  perichondrium  of  the  bones  and 
cartilages  of  the  nasal  fossa.  However,  considerable  variation  exists  in 
the  degree  of  the  closeness  of  the  connection  in  the  several  parts  of  the 
fossa.  The  respiratory  mucous  membrane  readily  thickens  under  patho- 
logic conditions,  often  attaining  a  thickness  from  four  to  six  times 
normal. 

The  stratiform  ciliated  cylindrical  epithelium  of  the  nasal  respiratory 
mucosa  rests  upon  a  cribriform  basement  membrane.  Ciliated  cells  ex- 
tend the  entire  thickness  of  the  epithelium ;  the  slender  ends  being  deeply 
placed,  resting  upon  the  basal  membrane,  and  the  more  bulky  ends  with 
the  attached  cilia  forming  the  free  surface.  The  cilia  are  least  developed 
over  the  superior  and  supreme  conchse.  They  attain  a  length  of  from 
5  to  7  microns  and  produce  a  definite  and  characteristic  current  toward 
the  choanse  (posterior  nares).  The  spaces  between  the  deeper  parts  of 
the  stratiform  cells  are  filled  with  irregularly  columnar  or  conical  cells. 
The  latter  rest  on  the  basement  membrane  but  never  reach  the  free  surface 
with  their  pointed  apices.  Moreover,  in  addition  to  the  conical  cells 
there  are  found  between  the  ciliated  cells,  resting  on  the  epithelial  floor. 


RESPIRATORY  PORTION 


263 


mucous-containing  goblet  cells.  Many  cellular  elements  are  encountered 
that  are  in  the  various  stages  of  conversion  into  goblet  cells.  Cement 
edges  are  demonstrable  between  the  more  superficial  ends  of  the  ciliated 
and  mucous  goblet  cells.  Migratory  leukocytes  are  numerous  among 
the  epithelial  elements. 

The  basement  membrane  (membrana  propria)  varies  greatly  in  thick- 
ness.    For   the   most   part   it   is   definitely   developed   and   fairly   well 


FIG.   181. — Section  of  mucous  membrane  from  the  caudal  portion  of  the  concha  nasalis  media. 
Note   the   excessive   number   of  glands.      X  95. 

marked;  however,  at  places  it  is  feeble  and  difficult  of  demonstration. 
Where  best  formed  it  may  normally  attain  a  thickness  of  0.020  mm.  or 
more.  It  is  distinctly  cribriform,  permitting  processes  of  connective- 
tissue  cells  and  leukocytes  to  pass  through  the  apertures  into  the  superim- 
posed epithelium.  The  apertures  in  the  basement  membrane  are  often 
referred  to  as  basal  canals,  and  as  Schiefferdecker  long  since  pointed  out, 


264  THE  NASAL  MUCOUS  MEMBRANE 

they  contain  connective-tissue  cells  and  leukocytes,  but  strangely  never 
blood  capillaries. 

The  tunica  propria  superficially  consists  of  loose  fibre-elastic  tissue, 
rich  in  cells,  and  here  and  there  collections  of  lymphocytes,  suggestive 
of  a  lymphoid  tissue  (lymphatic  nodules),  are  found.  Deeply,  as  the 
periosteum  and  perichondrium  are  approached,  the  tunica  propria  pro- 
gressively contains  more  abundant  networks  of  elastic  fibers.  There  is 


FIG.   182. — Section  of  mucous  membrane  from  concha  nasalis  inferior.     Note  the  fewer  glands  as 
compared  with  Pig.  181  and  the  large  number  of  cavernous  channels  (C).      X  95. 

great  variation  in  the  amount  of  elastic  fibers  that  are  developed;  at 
times  dense,  again  sparse. 

One  of  the  characteristics  of  the  nasal  respiratory  mucous  membrane 
is  the  extremely  rich  blood  supply  of  the  tunica  propria.  The  arteries 
of  the  deeper  strata  send  their  branches  through  the  propria  to  form  a 
capillary  network  beneath  the  epithelium  and  around  the  neighboring 
glands.  From  the  arterial  network  the  blood  flows  into  a  superficial 


RESPIRATORY  PORTION 


265 


venous  plexus,  thence  to  a  deeper  one.  Careful  study  indicates  that  these 
venous  plexuses  or  blood-sinuses  assume  the  character  and  role  of  an  erectile 
tissue — the  plexus  cavernosi  concharum.  The  latter  is  especially  developed 
over  the  inferior  concha  (Figs.  159  and  183),  along  the  dependent  border 
and  posterior  extremity  of  the  middle  concha,  and  along  adjacent  portions 
of  the  nasal  septum.  In  these  positions  one  finds  circular  and  longitudinal 
bundles  of  unstriped  muscle  embedded  in  the  walls  of  the  venous  channels 

Plezus  cavernosi  ctmchari&m, 

inferior) 


* 


TIMS*.   inferior 


FIG.  183.  —  Surface  section  of  mucous  membrane  from  the  concha  nasalis  inferior  as  seen 
through  the  binocular  microscope,  showing  the  cavernous  and  erectile  character  of  the  tunica 
propria.  X  12. 

or  vascular  areas  and  the  muscle  bundles  immeshed  in  a  connective-tissue 
stroma  containing  elastica.  Nerve  reflexes  control  the  filling  and  empty- 
ing of  the  cavernous  tissue.  It  is  well  known  that  certain  stimuli  through 
the  reflexes  rapidly  deplete  the  thickness  of  an  engorged  mucosa  and  that 
in  certain  psychic  states  similar  depletion  is  experienced,  and  vice  versa. 
The  great  masses  of  blood  are  doubtless  of  great  importance  in  warming  the 
inspired  air.  This,  indeed,  may  be  the  chief  function  of  the  erectile  tissue. 
Of  course,  a  possible  phylogenetic  relationship  must  be  kept  in  mind. 


266 


THE  NASAL  MUCOUS  MEMBRANE 


Numerous  glands  are  found  in  the  tunica  propria  of  the  respiratory 
mucous  membrane.  The  simplest  of  these  are  short  diverticula  of  the 
surface  epithelium,  dipping  into  the  underlying  tunica  propria,  which 
are  for  the  most  part  lined  with  goblet  cells.  Moreover,  many  branched 
tubo-alveolar  glands,  resembling  the  glands  of  the  lips,  are  found  which 
are  of  a  mixed  nature.  The  chief  ducts  of  these  open  on  the  free  surface 
by  minute  orifices.  The  deeper  portions  of  these  glands  branch  and 
rebranch  to  bear  the  ovoid  terminal  alveoli.  The  latter  are  lined  with 
mucous-secreting  cells  between  which  are  groups  of  serous  cells.  In 
addition  to  these  Kallius  encountered  purely  serous  glands  (Figs.  181  and 
182). 

The  Olfactory  Portion  (pars  olfactoria). — The  olfactory  portion  of 
the  nasal  mucous  membrane  is  limited  to  a  relatively  small  field  in  the 


Olfactory 


Olfactory  glands  -  -  - 
Blood  vessel- 


Olfactory  nerves . ___ zj^fft^- ~  ">:^.  Vx 

'"~ 


FIG.  184. 

FIG.   184. — Section    of    olfactory    mucous    membrane.       X  300. 
FIG.   185. — Isolated  olfactory  cells,  greatly  magnified.      {After  Schulze.) 


FIG.  185. 


nasal  fossa  as  indicated  at  the  beginning  of  this  chapter  and  delineated 
in  Figs.  19$  and  196.  It  is  demarked  from  the  respiratory  mucosa  of  the 
nasal  fossa  by  its  yellowish  color  and  greater  number  of  nuclei.  However, 
at  times  the  yellowish  appearance  is  wanting. 

The  olfactory  mucous  membrane  consists  of  a  surface  neuro-epithelium 
with  a  subjacent  tunica  propria.  A  definite  and  distinct  basal  membrane 
is  wanting.  The  neuro-epithelium  is  composed  of  specific  sensory 
(olfactory)  cells  and  sustentacular  (supporting)  and  basal  cells.  Col- 
lagenous  and  elastic  fibers  and  tubulo-acinar  serous  glands  (vide  infra) 
are  contained  in  the  tunica  propria  (Figs.  184  and  185). 

The  sustentacular  cells  are  tall,  columnar,  non-ciliated  epithelial  cells 


OLFACTORY  PORTION  267 

and  are  considerably  broader  than  the  olfactory.  Their  nuclei  contained 
in  the  outer  and  broader  ends  of  the  cells  are  ovoid  and  form  a  conspicuous 
nuclear  stratum.  There  is  a  clear  zone  devoid  of  nuclei  beneath  the  free 
surface  of  the  epithelium.  The  deep  ends  of  the  supporting  cells  often 
terminate  by  branching  into  two  or  more  processes,  in  the  intervals  of 
which  are  found  basal  cells.  The  cytoplasm  of  the  supporting  cells  is 
granular  and  frequently  contains  a  yellow  pigment. 

The  basal  cells  are  small,  flattened  pyramidal  elements  that  form  the 
deepest  nuclear  zone  of  the  olfactory  neuro-epithelial  layers  and  are  found 
between  the  branches  of  the  sustentacular  cells.  Their  nuclei  are  ovoid 
and  their  protoplasm  finely  granular.  They  may  represent  younger  and 
additional  forms  of  supporting  cells  of  the  olfactory  mucosa. 

The  olfactory  cells  are  the  perceptive  elements  of  the  nasal  mucosa. 
While  the  epithelium  of  the  embryological  olfactory  pits  is,  strictly  speak- 
ing, wholly  olfactory,  the  latter  designation  ultimately  applies  to  relatively 
few  cells  since  the  olfactory  function  is  lost  to  most  of  the  portions  of 
the  nasal  fossae.  The  cells  that  retain  the  olfactory  characters  and  func- 
tions are  known  as  neuroblasts.  They  remain  in  the  walls  of  the  nasal 
pits,  become  bipolar  olfactory  cells,  and  by  central  processes  become 
connected  with  the  brain.  They  represent  morphologically  the  ganglionic 
cells  on  the  dorsal  (sensory)  roots  of  the  spinal  nerves,  and  retain 
the  primitive  location  of  such  sensory  cells  in  the  surface  epithelium. 
The  olfactory  cells  are  unique  in  this  regard  among  neuro-epithelial 
elements. 

The  olfactory  cell  bodies  are  bipolar,  fusiform  and  contain  spherical 
nuclei  located  between  the  deeper  parts  of  the  supporting  columnar  cells. 
The  cells  extend  through  the  entire  thickness  of  the  neuro-epithelium. 
Their  peripheral  processes  are  short  and  pass  to  the  surface  of  the  mucosa 
through  openings  in  the  olfactory  limiting  membrane,  each  process  giv- 
ing rise  to  a  hemispherical  vesicle  which  in  turn  terminates  in  six  to  eight 
minute  hair-like  processes  of  fine  cilia — the  olfactory  hairs.  Moreover, 
the  olfactory  vesicles  and  processes  are  surrounded  and  in  a  sense  supported 
by  a  "semi-fluid  cuticle"  believed  to  be  secreted  by  the  supporting  cells. 
The  central  processes,  slender  and  often  tortuous,  become  grouped  into 
about  twenty  bundles,  the  olfactory  nerves,  and  pass  through  the  foram- 
ina of  the  lamina  cribrosa  of  the  ethmoid  bone  into  the  anterior  cerebral 
fossa,  and  after  piercing  the  meninges  of  the  brain  they  enter  the  olfactory 
bulb,  there  to  synapse  with  the  dendrites  of  the  mitral  cells  (see  page  332). 

Embryologically  the  lateral  evagination  of  the  olfactory  portion  of 
the  fore-brain  is  correlated  with  the  invagination  of  the  olfactory  epithe- 


268  THE  NASAL  MUCOUS  MEMBRANE 

lium  from  the  ectoderm,  and  throughout  life  these  two  parts  remain  in 
close  anatomical  and  physiological  relationships. 

The  tunica  propria  is  distinctly  differentiated  into  a  superficial  and  a 
deep  stratum.  The  superficial  stratum  consists  of  a  delicate  reticulated 
tissue  containing  many  irregularly  round  cells  resembling  lymphocytes. 
Indeed,  the  cells  are  at  places  so  closely  packed  as  to  suggest  small  lymph 
follicles.  On  the  other  hand,  the  deeper  stratum  contains  relatively  few 
cells,  but  dense  and  heavy  bundles  of  connective  tissue,  composed  of  col- 
lagenous  and  elastic  fibers. 

The  olfactory  (Bowman's)  glands  (glandulse  olfactoriae)  are  contained 
within  the  tunica  propria  of  the  olfactory  mucosa.  They  are  of  the 
branched  tubular  variety  and  open  on  the  free  surface  of  the  mucosa  by 
very  narrow  ducts  that  connect  with  saccular  fusiform  ampullae  into  which 
the  tubular  alveoli  open.  The  tubules  are  lined  with  cuboidal  or  conical 
cells  containing  many  albuminoid  secretory  granules,  not  unlike  those  of 
the  parotid  glands.  From  the  evidence  at  hand,  the  olfactory  glands 
should  be  classed  as  serous,  probably  elaborating  a  specific  secretion. 
The  ducts  of  the  glands  are  lined  throughout  the  interepithelial  course 
with  independent  flattened  cells  located  between  the  surrounding  epithe- 
lial elements. 

THE  PARANASAL  SINUSES 

The  paranasal  (accessory)  sinuses  are  lined  by  mucous  membrane 
directly  continuous  with  that  of  the  nasal  fossa,  including  the  maxillary, 
the  frontal  and  the  sphenoidal  sinuses;  and  the  ethmoid  labyrinth.  The 
mucous  membrane  lining  the  several  paranasal  sinuses  and  cells  resembles 
that  of  the  nasal  fossa  save  that  it  is  much  thinner  and  contains  fewer 
glands.  Moreover,  it  does  not  assume  the  characteristics  of  an  erectile 
tissue  (Figs.  186,  187,  and  188). 

The  mucous  membrane  of  the  paranasal  sinuses  and  cells  is  composed 
of  a  stratiform  ciliated  columnar  epithelium,  invaded  by  numerous 
lymphoid  elements,  resting  on  a  very  delicate  basal  membrane  and  tunica 
propria.  Indeed,  the  latter  is  firmly  adherent  to  the  underlying  perios- 
teum, especially  so  in  the  frontal  and  maxillary  sinuses,  less  in  the 
ethmoidal  labyrinth  and  still  less  in  the  sphenoidal  sinus.  Unlike  the 
mucous  membrane  of  the  nasal  fossae,  that  of  the  paranasal  sinuses  is 
poorly  supplied  with  elastic  fibers.  Moreover,  the  glands,  mucous 
in  type,  are  few  and  scattered  as  compared  with  the  glands  of  the  nasal 
cavity  proper.  In  the  maxillary  and  sphenoidal  sinuses  the  glands  are 
most  plentiful  in  the  vicinitv  of  the  ostia  of  the  cavities. 


PARANASAL  SINUSES 


269 


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270  THE  NASAL  MUCOUS  MEMBRANE 

In  spite  of  the  extreme  delicacy  and  thinness  of  the  mucous  membrane 
of  the  paranasal  sinuses  and  its  firm  adherence  to  the  periosteum,  it  is 
readily  influenced  and  greatly  thickened  by  pathologic  processes.  It 
is  particularly  prone  to  thickening,  rapidly  so,  in  the  vicinity  of  the  ostia 
of  the  maxillary  and  sphenoidal  sinuses  owing  to  the  greater  looseness 
of  structures  at  these  points. 

The  current  produced  by  the  cilia  of  the  epithelium  of  the  paranasal 
sinuses  is  toward  their  respective  ostia  or  apertures  of  communication 
with  the  nasal  fossa.  As  stated  elswhere,  the  current  produced  by  the 
cilia  of  the  epithelium  of  the  nasal  fossa  is  toward  the  choana  (posterior 
naris). 

THE  VOMERONASAL  ORGAN 

In  adult  man  in  the  caudo ventral  p  ortion  of  the  nasal  septum  slightly 
cephalic  and  ventral  to  the  orifice  of  the  nasopalatine  canal  may  occasion- 
ally be  found  a  small  ostium  leading  into  a  paired,  blindly  ending,  mucosa- 
lined  tubular  sac.  The  latter  courses  dorsalward  in  the  septal  mucosa 
for  a  distance  of  from  2  to  6  mm.,  is  lined  with  epithelium  continuous 
with  that  of  the  nasal  fossa,  and  has  numerous  glands  opening  into  its 
lumen. 

This  rudimentary  tubular  canal  is  the  homologue  of  a  highly  de- 
veloped tubular  organ,  the  vomeronasal  organ  (organon  vomeronasale 
Jacobsoni),  found  in  many  quadrupeds  in  which  the  olfactory  sense  is 
particularly  specialized.  In  the  latter  the  organ  is  supported  by  a  carti- 
lage (Jacobson's  cartilage).  However,  in  man  the  cartilage  of  Jacobson 
is  represented  by  a  rudimentary  strip  of  cartilage  (the  vomerine  cartilage 
of  Huschke)  located  caudal  to  both  the  septal  cartilage  and  the  rudi- 
mentary vomeronasal  organ  and  does  not  give  a  supporting  framework 
to  the  organ  as  it  does  in  other  animals. 

As  stated  elsewhere,  page  47,  the  vomeronasal  organ  in  man  ap- 
parently reaches  its  height  of  development  by  the  twentieth  week  of 
embryonal  life;  after  this  retrograde  changes  in  the  epithelium  occur 
(Fig.  189).  In  the  adult  the  organ  does  not  function  in  olf action;  no 
true  olfactory  cells  are  found  in  its  mucosa.  Most  of  the  cells  are  of  the 
sustentacular  type.  Some  spindle  cells  (probably  homologues  of  the  ol- 
factory cells)  are  found  between  the  latter  (especially  on  the  medial  wall) , 
but  do  not  reach  the  surface  and  apparently  are  not  connected  with  the 
olfactory  nerves  in  the  adult.  Read  found  olfactory  connections  in  the 
child  at  birth. 

In  some  other  animals,  e.g.,  the  rabbit,  etc.,  the  epithelium  of  the 


GENITAL  SPOTS 


271 


vomeronasal  organ  is  similar  in  structure  to  that  lining  the  olfactory 
mucous  membrane  of  the  nose  and  receives  branches  of  the  olfactory 
nerve  in  addition  to  branches  from  the  terminal  and  trigeminal  nerves. 
In  adult  man,  on  the  contrary,  the  vomeronasal  organ  seems  to  have  to 
do  wholly  with  general  sensation  and  is  supplied  by  the  terminal  and 
trigeminal  nerves  only. 


Fossa  itasalis 


Sepfor/t 


FIG.   189. — Frontal  section  through  the  nasal  fossae  and  the  nasal  septum  in  the  region  o>"  the  vomero- 
nasal organ  of  Jacobson.      X  133. 

THE  SO-CALLED  GENITAL  SPOTS 

Fleiss  (1897)  called  the  attention  of  rhinologists  and  gynecologists 
to  what  he  considered  an  important  relationship  between  certain  areas 
of  the  nasal  mucous  membrane  and  the  genitalia  and  adnexa.  He  be- 
lieved the  particular  spots  in  the  nasal  mucosa  to  be  limited  to  a  very 
small  area  on  the  tuberculum  septi,  directly  opposite  the  mid-portion 


272 


THE  NASAL  MUCOUS  MKMHKANK 


of  the  middle  nasal  concha,  and  to  the  ventral  portion  of  the  inferior 
nasal  concha.  Histologically,  there  is  nothing  apparently  that  character- 
izes these  areas  in  the  nasal  mucosa,  designated  by  Fleiss  uthe  genital 
spots."  Careful  examination  by  the  writer  of  the  erectile  portion  of 
the  nasal  mucosa  failed  to  reveal  any  characters  common  to  the  areas 
designated  by  Fleiss.  Further  study  by  a  more  perfected  technic 
may  show  a  difference  in  the  histology  of  the  so-called  genital  spots. 
This  is,  however,  doubtful. 

If  the  relationship  between  the  nasal  mucous  membrane  and  the 
genitalia  and  adnexa  becomes  established  in  dysmenorrhea  (not  taking 
into  consideration  the  obvious  reflex  connections  between  the  olfactory 
and  the  genital  organs),  it  is  more  than  likely  that  the  genital  spots  of 
Fleiss  will  be  found  to  conform  to  the  extent  of  the  erectile-tissue  portion 
of  the  nasal  mucosa  (see  page  265). 


IX-THE  BLOOD-  AND  LYMPH-VASCULAR  SYSTEMS 
OF  THE  NOSE  AND  PARANASAL  SINUSES 


CHAPTER  IX 

THE   BLOOD-   AND   LYMPH-VASCULAR   SYSTEMS  OF  THE  NOSE  AND 
PARANASAL  SINUSES 

THE  ARTERIAL  SUPPLY 

The  arterial  supply  of  the  nose  and  paranasal  sinuses  is  derived  from 
both  the  external  and  internal  carotid  systems.  Branches  of  the  ophthal- 
mic from  the  internal  carotid  and  the  external  maxillary  (facial)  and  the 
internal  maxillary  from  the  external  carotid  are  concerned  in  the  nasal 
supply.  The  final  arterial  distribution  is  effected  by  capillary  plexuses 
or  networks  which  supply  the  mucoperiosteum  (periosteum,  glands  and 
tunica  propria);  one  lying  deep  in  the  periosteum,  a  second  surrounds 
and  immeshes  the  glands,  and  a  third  forms  a  network  immediately  be- 
neath the  epithelium. 

The  Sphenopalatine  Artery. — The  main  arterial  supply  to  the  nasal 
fossa  and  its  appendages  is  distributed  through  the  sphenopalatine  artery 
(a.  sphenopalatina),  the  terminal  branch  of  the  internal  maxillary  artery 
(a.  maxillaris  interna) .  The  sphenopalatine  enters  the  nasal  fossa  through 
the  sphenopalatine  foramen  (foramen  sphenopalatinum)  which  is  located 
on  the  lateral  nasal  wall  near  the  dorsal  extremity  of  the  superior  nasal 
meatus  and  is  formed  by  the  articulation  of  the  perpendicular  plate  of  the 
palate  bone  with  the  caudal  surface  of  the  sphenoid  bone.  In  the  recent 
state  the  foramen  is  covered  over  by  the  nasal  mucosa. 

In  the  passage  of  the  sphenopalatine  artery  through  the  foramen  on 
the  lateral  nasal  wall  it  is  accompanied  by  branches  of  the  sphenopalatine 
nerve,  and  immediately  upon  its  appearance  in  the  nasal  fossa  it  gives 
off  a  small  branch  which  aids  in  the  supply  of  the  mucous  membrane  of 
the  sphenoidal  sinus,  and  another  variable  branch  whic  at  times  replaces 
the  pharyngeal  artery  and  has  a  similar  distribution  (see  pharyngeal 
artery).  The  main  trunk  of  the  sphenopalatine  artery  now  divides  into 
a  large  medial  and  a  large  lateral  branch  (Fig.  190). 

The  lateral  branch  of  the  sphenopalatine  artery  breaks  up  into  a  number 
of  secondary  rami,  the  lateral  posterior  nasal  arteries  (aa.  nasales  pos- 
teriores  laterales),  which  ramify  cranial-,  caudal-,  and  ventral  ward  from 
the  choanse  to  the  nares  and  anastomose  with  the  anterior  and  posterior 
ethmoidal  arteries  and  with  the  lateral  nasal  branch  of  the  external  maxil- 

275 


276 


THK   BLOOD-  AND  LYMPH-VASCULAR  SYSTI.MS 


lary  (facial)  artery.  The  group  of  lateral  posterior  nasal  arteries  form  a 
rich  plexus  in  the  mucous  membrane  lining  the  nasal  meatuses  and  con- 
chae,  the  maxillary  and  frontal  sinuses,  and  the  ethmoidal  cells. 

The  medial  branch  of  the  sphenopalatine  artery,  the  nasopalatine 
artery  (a.  nasopalatina),  courses  transversely  across  the  roof  of  the  nasal 
fossa  to  reach  the  medial  nasal  (septal)  wall.  Here  the  branch  suffers 
dissociation  into  secondary  rami,  the  posterior  nasal  septal  arteries  (aa. 

A.ethmoidcUis  anterior 

A.ethmoidalis  posterior 

Sinus  spTtenoidalis 

,  &phc.nop>a.2a,tina. 


A.pcJa,tina,  major  Aa.nasalespostcrioreslaterales 

FIG.   190. — The  arteries  of  the  lateral  wall  of  the  nasal  fossa. 

nasales  posteriores  septi),  which  form  a  rich  network  beneath  and  in  the 
septal  mucous  membrane.  These  arteries  variously  anastomose  with  the 
anterior  and  posterior  ethmoidal  arteries,  with  the  septal  branch  of  the 
superior  labial  artery,  and  with  the  great  palatine  (anterior  branch  of  the 
descending  palatine)  artery  near  or  within  the  incisive  (anterior  palatine) 
foramen.  Some  of  the  posterior  nasal  septal  arteries  are  accompanied 
by  the  nasopalatine  nerve  in  its  course  across  the  nasal  septum  to  the  in- 
cisive foramen  (Fig.  191). 


ARTERIAL  SUPPLY 


277 


The  Anterior  and  Posterior  Ethmoidal  Arteries. — The  anterior  and 
posterior  ethmoidal  arteries  arise  from  the  ophthalmic  artery  (a.  ophthal- 
mica)  as  the  latter  courses  along  the  medial  wall  of  the  orbit.  Occasion- 
ally the  posterior  ethmoidal  arises  from  the  supraorbital  artery. 

The  anterior  ethmoidal  artery  (a.  ethmoidalis  anterior),  accompanied 
by  the  anterior  ethmoidal  branch  of  the  nasociliary  nerve,  passes  through 
the  anterior  ethmoidal  foramen  on  the  ventromedial  aspect  of  the  orbit 
into  the  anterior  cerebral  fossa.  In  its  course  ventral  ward  along  the 


A.  ethmoidalis  anterior 

A.  ethm.oida2is  posterior 


,Aa,.7iasaZes  posteriores  septi 
\  fnasopaZatineJ 

Fossa,  kypophyseos 


Aitastomosis 


Apoiloitina,  major 


FIG.   191. — The  arteries  of  the  medial  or  septal  wall  of  the  nasal  fossa. 

cranial  surface  of  the  cribriform  plate  of  the  ethmoid  bone,  the  anterior 
ethmoidal  artery  supplies  branches  to  the  dura  mater  and  to  the  mucous 
membrane  of  the  frontal  sinuses  and  the  anterior  ethmoidal  cells,  and  ulti- 
mately passes  through  a  slit-like  foramen  at  the  side  of  the  crista  galli 
to  reach  the  mucous  membrane  of  the  nasal  fossa.  Once  in  the  nasal 
fossa  the  anterior  ethmoidal  artery  descends,  accompanied  by  the  lateral 
branch  of  the  nasal  nerve,  in  a  groove  on  the  deep  surface  of  the  nasal 
bone  and,  finally,  courses  between  the  lateral  nasal  cartilage  and  the 
caudal  (lower)  border  of  the  nasal  bone  to  the  tip  of  the  nose.  In  the 


278  THE  BLOOD-  AND  LYMPH-VASCULAR  SYSTEMS 

nose  the  artery  supplies  branches  to  the  nasal  mucoperiosteum  along  its 
course  and  to  the  integument  on  the  dorsum  of  the  nose  (Figs.  190,  191). 
The  posterior  ethmoidal  artery  (a.  ethmoidalis  posterior)  is  smaller 
and  less  constant  than  the  anterior  ethmoidal  above  described.  It  passes 
through  the  posterior  ethmoidal  foramen  on  the  dorsomedial  aspect  of 
the  orbit  and  is  distributed  to  the  mucoperiosteum  lining  the  posterior 
ethmoidal  cells  and  the  dorsal  and  superior  portions  of  the  nasal  septum 
and  the  lateral  nasal  wall.  Here  the  posterior  ethmoidal  branch  of  the 
ophthalmic  artery  and  the  sphenopalatine  branch  of  the  internal  maxillary 
artery  connect  up  in  a  plexiform  anastomosis  (Figs.  190  and  191). 

The  Descending  Palatine  Artery. — The  descending  palatine  artery 
(a.  palatina  descendens),  a  branch  of  the  internal  maxillary,  supplies  small 
branches  to  the  dorsal  portion  of  the  nasal  fossa  and  by  its  direct  ventral  con- 
tinuation— the  great  palatine  artery,  which  courses  forward  in  the  roof  of  the 
mouth  to  ascend  through  the  incisive  foramen — supplies  a  portion  of  the 
nasal  fossa  in  the  neighborhood  of  the  incisive  foramen  where  it  anasto- 
moses with  the  posterior  artery  of  the  septum  nasi  (the  nasopalatine  artery). 

The  Pharyngeal  Artery. — The  pharyngeal  artery  (a.  pharyngea), 
a  small  branch  of  the  internal  maxillary,  courses  dorsalward,  accompanied 
by  the  pharyngeal  branch  of  the  sphenopalatine  ganglion,  through  the 
pharyngeal  canal  (canalis  pharyngeus)  to  the  roof  of  the  pharynx.  From 
here  the  artery  distributes  small  branches  to  the  dorsal  and  superior 
portions  of  the  nasal  fossa,  the  roof  of  the  pharynx,  the  sphenoidal  sinus 
and  the  auditory  tube. 

The  Infra  orbital  Artery. — The  maxillary  sinus,  in  addition  to  the  blood 
supply  from  the  lateral  nasal  branches  of  the  sphenopalatine  artery, 
receives  abundant  supply  from  the  branches  of  the  infraorbital  artery 
(a.  infraorbitalis). 

The  External  Maxillary  (Facial)  Artery. — The  nares  (nostrils)  of 
the  nose  are  supplied  by  the  lateral  nasal  branch  of  the  external  maxillary 
(facial)  and  by  the  septal  branch  from  the  superior  labial  (a.  labialis 
superior  or  coronary  artery).  The  external  maxillary  or  facial  artery 
continues  along  the  lateral  aspect  of  the  external  nose  as  the  angular 
artery  (a.  angularis)  and  anastomoses  with  the  true  terminal  branch  (a. 
dorsalis  nasi)  of  the  ophthalmic  artery.  This  anastomosis  supplies  the 
integument  over  the  side  and  dorsum  of  the  external  nose. 

THE  VENOUS  SUPPLY 

The  veins  of  the  nose  form  a  great  network  in  the  deeper  parts  of  the 
tunica  propria  of  the  nasal  mucous  membrane,  which  in  the  respiratory 


LYMPHATIC  SUPPLY 


279 


region  over  the  middle  and  inferior  nasal  conchae  and  the  adjacent  por- 
tions of  the  nasal  septum  assumes  the  character  of  a  dense  cavernous 
plexus.  Elsewhere  the  erectile  character  of  the  network  is  less  marked 
or  absent  altogether. 

The  venous  blood  is  returned  from  the  plexiform  network  by  three 
chief  pathways:  ventrally  into  the  anterior  facial  vein,  dorsally  into  the 
sphenopalatine  vein,  and  cranially  into  the  ethmoidal  veins.  Injections 
show  that  the  ethmoidal  veins  communicate  with  the  ophthalmic  vein 
and  with  the  veins  within  the  dura  mater,  including  the  superior  sagittal 


Posterior  ciliary  vein 
Superior  ophthalmic  vein 


Optic  nerve 
Cavern 


Supraorbital  vein 
communicating 
with  nasofrontal 

Frontal  vein 
Lacrimal  gland 


Internal  maxil- 
lary vein 


Posterior  facial 
vein 


Anterior  facial  vein 
PIG.   192. — The  veins  of  the  nose  and  eye  and  their  connections.     (After  Quain.) 

dural  sinus.  Moreover,  Zuckerkandl  found  that  an  anterior  ethmoidal 
vein  leads  from  the  nasal  mucosa  and  passes  through  the  cribriform  plate 
to  end  in  the  venous  plexus  of  the  olfactory  bulb  or  in  one  of  the  veins 
on  the  orbital  aspect  of  the  frontal  lobe  of  the  brain.  These  venous 
communications  must  be  a  factor  in  the  intracranial  complications  that 
frequently  accompany  or  follow  some  cases  of  inflammation  of  the  nasal 
cavities  and  paranasal  sinuses  (Fig.  192). 

THE  LYMPHATIC  SUPPLY 

The  existence  of  lymphatics  in  the  nasal  mucosa  was  first  satis- 
factorily demonstrated  by  E.  Simon  in  1859.  He  succeeded  by  puncture 
injections  in  demonstrating  an  extensive  network  of  lymphatic  vessels. 


280 


THE  BLOOD-  AND  LYMPH-VASCULAR  SYSTEMS 


This  network  is  continuous  with  the  lymphatic  vessels  of  the  nasopharynx, 
the  nasal  vestibule  and  the  cephalic  and  dorsal  surfaces  of  the  soft 
palate.  Moreover,  there  is  a  lymphatic  connection  between  the  two 
nasal  fossae. 

The  Nasal  Cavity. — The  lymphatics  of  the  nasal  cavity  ramify 
the  entire  mucoperiosteum,  both  olfactory  and  respiratory,  including 
that  of  the  septum.  It  has  also  been  fairly  well  established  that  the 
lymphatic  network  extends  into  the  paranasal  (accessory)  sinuses  in 
communication  with  the  nasal  cavity.  The  lymphatic  vessels  are  located 
in  the  connective  tissue  of  the  tunica  propria  and  their  richness  is  in 
direct  proportion  to  the  thickness  of  the  mucosa.  At  places  the  mucosa 


FIG.   193. — The  lymphatics  of  the  nasal  fossa.     (Redrawn  from  Testul.) 

At  =  Anterior  lymphatic  channels;  Pt  =  Posterior  lymphatic  channels;  Sm  =  Submandibular 
or  submaxillary  group  of  lymphatic  nodes;  R p  =  Retropharyngeal  group  of  lymphatic  nodes;  DC  = 
Deep  cervical  group  of  lymphatic  nodes. 

is  infiltrated  with  lymphocytes  and  occasionally  very  minute  solitary 
nodules  are  found.  In  man  the  main  collecting  vessels  of  the  lymphatic 
network  of  the  nasal  fossae  form  ventral  and  dorsal  groups.  The  ventral 
(anterior)  group  vary  in  number  and  are  found  to  course  in  the  groove 
between  the  triangular  cartilage  and  the  bordering  bone  and  between  and 
ectal  to  the  several  cartilages  of  the  external  nose.  In  the  subcutaneous 
tela  they  unite  into  several  large  trunks  in  relation  with  the  facial  nerve. 
These  collecting  trunks  empty  into  the  facial  and  the  submandibular 
(submaxillary)  groups  of  nodes.  Furthermore,  there  is  considerable 
anastomosis  with  the  skin  lymphatics  of  the  external  nose. 

The   lymphatic   network  in  the  region  ventral  and  caudal  to  the 


LYMPHATICS  OF  NASAL  CAVITY  281 

pharyngeal  ostium  of  the  auditive  (Eustachian)  tube  receives  drainage 
from  a  considerable  portion  of  the  nasal  fossa.  From  this  region  go  forth 
the  largest  and  most  important  collecting  trunks  from  the  lymphatic 
network,  to  terminate  in  either  the  deep  cervical  chain  or  in  the  retro- 
pharyngeal  nodes.  It  has  been  shown  by  Most  that  at  whatever  point 
the  nasal  mucosa  is  punctured,  the  retropharyngeal  nodes  are  colored 
by  the  injected  material.  Sappey  long  since  pointed  out  the  involvement 
of  the  large  lateral  retropharyngeal  nodes  ventrad  of  the  atlas  in  diseases 
of  both  the  nose  and  the  pharynx.  The  frequent  infection  of  the  retro- 
pharyngeal nodes  is  readily  explained  when  one  recalls  their  extensive 
lymphatic  area.  They  receive  as  afferents  almost  all  the  collecting  vessels 
from  the  nasal  mucous  membrane  and  from  the  cavities  in  connection  with 
the  nasal  fossae.  Moreover,  afferents  from  the  lymphatic  network  of  the 
cavity  of  the  tympanum,  the  auditive  tube,  and  the  nasopharynx  pass 
to  these  regional  nodes  (Fig.  193). 

It  would  appear  established  that  the  subdural  space  directly  com- 
municates with  the  extracranial  lymphatics  and  the  perineural  spaces  of 
the  olfactory  nerve,  etc.  Schwalbe,  Key  and  Retzius,  and  subsequently 
Cuneo,  succeeded  in  injecting  the  nasal  lymphatics  from  the  subdural 
spaces.  Furthermore,  Key  and  Retzius  reported  success  in  injecting 
the  nasal  lymphatics  from  the  subarachnoid  spaces  at  the  base  of  the  brain. 
Confirmation  of  the  latter  is,  however,  lacking  at  this  date  and  it  is  probable, 
according  to  other  studies,  that  the  subarachnoid  space  has  no  direct 
lymphatic  connections.  The  perineural  sheaths  of  the  olfactory  nerves 
are  of  interest  in  this  connection.  Key  and  Retzius  found  that  when  in- 
jecting the  subarachnoid  space  the  perineural  sheaths  of  the  olfactory 
nerves  would  frequently  be  injected.  They  found,  however,  that  the 
true  lymphatics  did  not  communicate  with  these  perineural  sheaths,  but 
had  special  passages  through  the  lamina  cribrosa  and  that  they  were  often 
injected  when  the  perineural  sheaths  were  not  injected.  On  the  contrary, 
the  perineural  sheaths  were  at  times  injected  and  the  lymphatics  not. 

Flexner,  in  discussing  the  mode  of  infection  in  epidemic  meningitis, 
states  that  in  all  probability  the  micro-organism  passes  directly  to  the 
nervous  system  by  way  of  the  lymphatic  connections  between  the  naso- 
pharyngeal  mucosa  and  the  meninges. 

The  Paranasal  Sinuses. — There  is  little  definite  knowledge  regarding 
the  lymphatics  of  the  paranasal  (accessory)  sinuses  of  the  nose.  Studies 
of  Most  indicate  that  the  lymphatic  drainage  from  all  the  paranasal  sinuses 
and  cells  is  into  the  retropharyngeal  nodes.  Clinical  evidence  bears 
out  this  conclusion. 


282 


THE  BLOOD-  AND  LYMPH- VASCULAR  SYSTK.MS 


The  External  Nose. — The  lymphatic  network  of  the  external  nose 
is  very  dense  over  the  alae  and  lobules  and  as  it  courses  over  the  dorsum 
and  the  root  of  the  organ.  There  is  an  anastomosis  from  side  to  side. 
As  pointed  out  before,  the  lymphatic  network  of  the  external  nose  is  con- 
tinuous with  the  lymphatics  of  the  nasal  vestibule  and  the  mucosa  of  the 
nasal  fossae.  The  collecting  vessels  arise  from  the  cutaneous  network 
in  three  groups,  according  to  the  studies  of  Kiittner:  (a)  from  the  root 
of  the  nose  they  pass  above  the  upper  eyelid  and  terminate  in  the  parotid 
nodes;  (b)  from  the  root  and  side  of  the  nose  they  pass  across  the  lower 


sm 


FIG.   194. — Schema  of  the  lymphatics  of  the  external  nose.      (Redrawn  from  Testut,  after  T.  el  J.) 
I    =  Superior  group  of  lymphatic  channels;  2    =  Middle  group  of  lymphatic  channels;  3    =  Inferior 
group  of  lymphatic  channels;  p    =  Parotid  group  of  lymphatic  nodes;  sm    =  Submandibular  (sub- 
maxillary)  group  of  lymphatic  nodes. 

eyelid  to  the  parotid  nodes;  (c)  the  third  and  most  important  group  arise 
from  the  entire  cutaneous  portion  of  the  external  nose  and  terminate  in 
either  the  facial  or  submandibular  (submaxillary)  group  of  nodes.  Kiitt- 
ner was  able  by  puncturing  the  integument  of  the  external  nose  to  distend 
the  lymphatics  of  the  mucosa  of  the  nasal  fossae  and  to  follow  the  in- 
jection to  the  dorsal  surface  of  the  soft  palate  (Fig.  194). 

Further  study  of  the  nasal  lymphatics  is  necessary  in  the  light  of 
certain  clinical  manifestations. 


X-THE  COMMON  SENSORY  AND  THE  SYMPA- 
THETIC NERVES  OF  THE  NOSE  AND 
PARANASAL  SINUSES 


CHAPTER  X 

THE   COMMON   SENSORY   AND   THE   SYMPATHETIC  NERVES  OF  THE 
NOSE  AND  PARANASAL  SINUSES 

A.  THE  NERVES  OF  COMMON  SENSATION 

The  nerves  of  common  sensation  of  the  nose  and  its  appendages  are 
derived  from  both  the  ophthalmic  and  the  maxillary  divisions  of  the  tri- 
geminal  nerve  (n.  trigeminus),  e.g.,  the  nervus  ophthalmicus  and  the  nervus 
maxillaris,  respectively.  The  sensory  nerves  to  the  nose  are  in  reality 
peripheral  processes  of  T-fibers  which  spring  from  the  nerve  cell  bodies 
(perikaryons)  of  the  semilunar  (Gasserian)  ganglion  and  pass  to  the  nasal 
organ  by  way  of  the  branches  of  the  ophthalmic  and  maxillary  trunks  of 
the  ganglion.  The  central  processes  of  the  T-fibers,  on  the  contrary,  pass 
into  the  brain  stem,  there  to  synapse  at  the  nucleus  of  termination  of  the 
trigeminal  nerve  with  neurons  of  the  second  order  in  the  common  sensory 
(afferent)  pathway  from  the  nose.  The  cell  bodies  of  the  semilunar  gan- 
glion together  with  the  T-fibers  with  their  central  and  peripheral  processes 
constitute  neurons  of  the  first  order  in  the  common  sensory  pathway.  It 
would  appear  established  that  the  trigeminal  nerve  fibers  rise  up  between 
the  epithelial  cells  of  the  nasal  mucous  membrane  and  end  free.  The 
"Geruchsknospen"  of  Blaue  and  the  "Epithelknospen"  of  Disse  need 
re-investigation. 

The  Central  Connections. — The  sensory  (terminal)  nucleus  of  the 
trigeminal  nerve  is  located  in  the  pons  lateral  to  the  motor  one  (nucleus 
of  origin  of  the  masticator  nerve)  and  beneath  the  brachium  conjunctivum 
(superior  cerebellar  peduncle).  It  consists  of  an  enlarged  upper  end,  usu- 
ally referred  to  as  the  main  sensory  nucleus,  and  an  elongated,  slender 
descending  portion — the  nucleus  of  the  spinal  tract  of  the  trigeminal  nerve. 
The  latter  extends  through  the  pons  and  the  medulla  and  becomes  con- 
tinuous with  the  dorsal  part  of  the  posterior  column  of  gray  matter  of 
the  spinal  cord,  particularly  the  substantia  gelatinosa  of  Rolando.  The 
main  sensory  nucleus  receives  the  short  ascending  branches;  the  descend- 
ing branches  collectively  forming  the  tractus  spinalis  which  ends  by  termi- 
nals and  collaterals  in  the  several  portions  of  the  nucleus  of  the  spinal 

285 


286  THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 

tract,  extending  through  the  pons,  medulla  and  spinal  cord  to  the  level 
of  the  second  cervical  segment. 

The  cells  of  the  sensory  or  terminal  nucleus  of  the  trigeminal  nerve 
together  with  their  processes  constitute  neurons  of  the  second  order  in 
the  common  sensory  pathway  from  the  nose.  The  centrally  directed 
processes  or  axons  form  a  distinct  bundle,  the  trigeminothalamic  tract, 
which  passes  cranialward  through  the  reticular  formation  and  the  teg- 
mentum  to  end  in  a  special  portion  of  the  thalamus  by  synapsing  with  the 
neurons  of  the  third  order  in  the  pathway  from  the  nose  to  the  cerebral 
cortex.  For  the  most  part  the  fibers  of  the  trigeminothalamic  or  central 
trigeminal  tract  decussate  or  cross  to  form  the  opposite  paired  tract, 
ascending  dorsal  to  the  medial  fillet  or  lemniscus.  A  few  fibers  of  the 
trigeminothalamic  tract  ascend  to  the  thalamus  uncrossed.  From  the 
thalamus  impulses  are  carried  over  neurons  of  the  third  order  to  the  somes- 
thetic  area  of  the  cerebral  cortex,  the  axons  of  which  course  by  way  of  the 
internal  capsule  and  the  corona  radiata,  mostly  on  the  side  opposite  from 
which  the  impulse  initially  started  in  the  nose.  Thus  stimulation  of  the 
terminal  nucleus  of  the  trigeminal  nerve  leads  to  conscious  sensations,  often 
of  a  painful  character.  Some  fibers  of  both  the  trigeminal  nerve  direct 
and  from  its  terminal  nucleus  pass  laterally  into  the  cerebellum. 

Axons  from  the  nucleus  of  termination  of  the  trigeminal  nerve  and 
collaterals  from  the  trigeminothalamic  tract  in  its  course  through  the 
medulla  are  given  to  various  motor  nuclei,  especially  the  facial,  the  masti- 
cator (motor  of  trigeminal),  and  the  nucleus  ambiguus  (of  the  vagus  and 
glossopharyngeal  nerves)  for  simple  reflexes.  Moreover,  some  of  the 
reflex  or  association  axons  from  cells  in  the  nucleus  of  termination  of  the 
trigeminal  nerve  contribute  fibers  to  the  medial  longitudinal  fasciculus, 
some  of  which  are  long  and  descend  below  the  level  of  the  second  cervical 
segment,  terminating  in  the  gray  substance  of  the  spinal  cord.  Since  one 
of  the  salient  features  of  the  medial  longitudinal  fasciculus  is  to  associate 
the  oculomotor,  trochlear  and  abducent  nuclei,  the  association  axons 
from  the  trigeminal  terminal  nucleus  coursing  in  the  bundle  doubtless 
are  brought  into  relationship  with  the  nuclei  of  the  eye-moving  muscles, 
and  since  the  fasciculus  becomes  continuous  with  the  anterior  fasciculus 
proper  of  the  spinal  cord,  relationship  is  also  established  between  the 
association  axons  and  the  ventral  horn  cells  of  the  cervical  spinal  segments. 

Relations  are  also  established  between  the  central  trigeminal  fibers 
and  their  terminal  nucleus  and  the  vasoconstrictor,  vasoinhibitor  and 
secretomotor  centers.  Stimulation  of  the  latter  centers  leads  to  un- 
conscious sensations,  resulting  in  divers  reflex  phenomena. 


SYMPATHETIC  NERVES  287 

The  somatic  sensory  fibers  of  the  vagus,  of  the  glossopharyngeal  and 
of  the  pars  intermedia  of  the  facial  nerves  terminate  in  the  nucleus  of  the 
spinal  tract  of  the  trigeminal  nerve  and  their  cortical  impulses  follow  the 
trigeminothalamic  tract.  The  descending  somatic  sensory  fibers  of  the 
vagus,  glossopharyngeal  and  facial  (pars  intermedia)  nerves  which  termi- 
nate in  the  spinal  tract  of  the  trigeminal  nerve,  doubtless  through  the 
medium  of  associational  or  connecting  neurons,  establish  relations  with 
the  nuclei  of  the  motor  cranial  nerves  in  the  medulla  and  with  the  ventral 
or  motor  horn  cells  of  the  high  spinal  cord. 

B.  THE  SYMPATHETIC  NERVES 

Xerve  impulses  destined  to  determine  the  caliber  of  the  blood-vessels 
and  to  control  the  mechanism  of  secretion  in  and  about  the  nasal  fossas 
are  transmitted  by  sympathetic  efferent  nerves.  Both  the  cranial  and 
the  thoracolumbar  sympathetics  have  to  do  with  the  nasal  supply;  the 
cranial  brought  about  by  sympathetic  fibers  contained  in  the  pars  inter- 
media of  the  facial  nerve  and  the  thoracolumbar  by  connections  between 
the  upper  thoracic  segments  of  the  medulla  spinalis  (spinal  cord)  and  the 
superior  cervical  sympathetic  ganglion.  Moreover,  it  is  believed  that 
certain  impulses  from  the  nasal  mucous  membrane  reach  the  cerebro- 
spinal  nervous  system  over  sympathetic  afferent  nerves. 

The  term  "sympathetic"1  is  used  advisedly  since  it  is  a  term  generally 
understood  to  apply  to  that  portion  of  the  peripheral  nervous  system  which 
innervates  the  smooth  or  visceral  muscles  wherever  located,  the  various 
glands  of  the  body,  and  the  striated  muscle  of  the  heart.  It  is  not  deemed 
profitable  nor  essential  in  this  connection  to  discuss  the  detailed  anatomy 
of  the  sympathetic  nervous  system.  The  reader  is  referred  to  special 
treatises  on  the  subject.  It  must,  however,  be  clearly  understood  that 
on  the  efferent  (motor)  side  of  the  sympathetic  system  there  are  two  orders 
of  neurons  connecting  the  cerebrospinal  axis  with  the  tissue  or  organ  sup- 
plied. The  neurons  of  the  first  order  (preganglionic)  have  their  cell  bodies 
within  either  the  brain  or  the  spinal  cord,  the  peripheral  processes  (axons) 
terminating  by  synapsing  in  sympathetic  ganglia  with  the  cell  bodies  of 
neurons  of  the  second  order  (postganglionic),  whose  peripheral  processes 
or  axons  extend  to  the  parts  to  be  acted  upon.  This  stands  in  contrast  to 
the  single  lower  motor  neurons  of  the  somatic  series  of  nerves  in  which  the 
cell  bodies  are  also  located  within  the  cerebrospinal  axis,  but  whose  axons 

1  The  terms  autonomic  (Langley),  vegetative  (Myer  and  Gottlieb)  and  involuntary  (Gaskell) 
are  frequently  applied  to  the  sympathetic  system.  Langley  limited  the  term  sympathetic  to  apply 
to  the  thoracolumbar  outflow.  There  is,  however,  no  morphologic  basis  for  this  distinction. 


288  THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 

go  directly  to  the  striated  or  voluntary  muscles  without  further  synapse. 
Furthermore,  it  is  essential  to  recall  that  the  vast  majority  of  the  cell 
bodies  or  perikaryons  of  the  afferent  or  sensory  sympathetic  neurons  are 
located  in  the  ganglia  on  the  dorsal  roots  of  the  spinal  nerves  and  in 
homologous  ganglia  of  certain  cranial  nerves.  Cell  bodies  of  a  few  afferent 
sympathetic  neurons  are  apparently  located  in  the  extra-centrally  placed 
sympathetic  ganglia. 

It  is,  therefore,  obvious  that  the  only  anatomically  independent 
units  of  the  sympathetic  nervous  system,  so  far  as  a  connection  with  the 
cerebrospinal  nervous  system  is  concerned,  are  the  postganglionic  neurons 
with  cell  bodies  in  the  sympathetic  ganglia  and  whose  axons  collectively 
course  as  pure  sympathetic  nerves  or  as  sympathetic  components  of 
somatic  nerves  to  the  various  parts  of  the  body.  Moreover,  in  spite  of  a 
certain  peripheral  autonomy  in  the  physiologic  responses  of  the  sympa- 
thetic nervous  system,  the  latter  is  in  large  measure  regulated  and  con- 
trolled by  the  cerebrospinal  nervous  system,  a  control  made  possible 
by  the  intimate  anatomic  connections  of  the  two  systems. 

Sympathetic  Efferent  Neurons. — A.  Sympathetic  efferent  or  motor 
fibers  for  the  supply  of  the  nasal  fossae  and  sinuses  arise  from  a  special 
nidus  of  cells  located  dorsal  and  medial  to  the  facial  nucleus  in  the  reticular 
formation  of  the  medulla.  The  preganglionic  fibers  from  this  nest  of  cells 
leave  the  medulla  as  constituent  elements  of  the  pars  intermedia  of  the 
facial  nerve  (the  glossopalatine  nerve),,  and  are  distributed  (i)  by  the 
chorda  tympani  and  lingual  nerves  to  the  sub  maxillary  ganglion  and  (2) 
by  the  great  superficial  petrosal  nerve  to  the  sphenopalatine  (Meckel's, 
nasal)  ganglion.  From  the  cell  bodies  located  in  the  sympathetic  sub- 
maxillary  ganglion  go  forth  postganglionic  fibers,  vasodilator  and  secretory 
in  function,  to  the  submaxillary  and  sublingual  salivary  glands;  and  from 
the  cell  bodies  in  the  sympathetic  sphenopalatine  ganglion  issue  post- 
ganglionic fibers  (in  the  branches  of  the  sphenopalatine  ganglion,  see 
page  307),  vasodilator  and  secretory  in  function,  to  the  mucous  membrane 
(blood-  and  lymph-vessels  and  glands)  of  the  nose  and  palate,  the  lacrimal 
gland,  the  tonsils,  etc. 

B.  Sympathetic  efferent  (preganglionic}  fibers  with  cell  bodies  located 
in  the  dorsolateral  portion  of  the  ventral  horns  of  the  upper  four  or  five 
thoracic  segments  leave  the  spinal  cord  by  the  ventral  roots  of  the  cor- 
responding spinal  nerves  and  reach  the  ganglionated  sympathetic  cord 
by  way  of  white  rami  communicantes.  The  axons  of  most  of  these 
preganglionic  neurons,  destined  for  the  supply  of  the  various 
parts  of  the  head,  ascend  in  the  cervical  sympathetic  cord  and 


SYMPATHETIC  AFFERENT  NEURONS  289 

terminate  by  synapsing  around  the  cell  bodies  of  postganglionic  neurons 
located  in  the  superior  cervical  sympathetic  ganglion.  The  latter  neu- 
rons are  variously  vasodilator,  vasoconstrictor,  secretory,  visceromotor  (to 
the  dilator  pupillae  muscle)  in  function.  They  ascend  by  way  of  the 
cephalic  plexiform  extension  of  the  superior  cervical  sympathetic  ganglion 
and  reach  their  destination  by  way  of  cranial  nerves,  especially  the  branches 
of  the  trigeminal.  Some  of  these  postganglionic  neurons  furnish  vaso- 
constrictor, and  probably  additional  dilator  and  secretory  fibers,  to  the 
nasal  mucous  membrane. 

Probably  the  pars  intermedia  and  the  cervical  ganglionated  cord 
carry  both  vasoconstrictor  and  vasodilator  preganglionic  fibers;  but 
that  the  vasodilator  fibers  are  most  numerous  and  active  in  the  pars 
intermedia  and  the  vasoconstrictor  in  the  cervical  extension  from  the 
sympathetic  (at  least  so  far  as  the  nasal  mucous  membrane  is  concerned) 
seems  certain.  Of  course,  when  experimentally  stimulating  these  nerves 
the  work  of  the  fewer  and  less  active  fibers  may  be  wholly  masked  by  the 
greater  effect  and  number  of  antagonistic  fibers.  In  general,  throughout 
the  body,  the  vasoconstrictor  fibers  are  the  most  prominent,  exercising 
a  continual  tonic  effect  on  blood-vessels.  However,  while  vasodilator 
fibers  are  fewer  and  less  frequently  seen  in  action,  they  do  exist — striking 
illustrations  are  the  chorda  tympani  in  its  action  on  the  submaxillary 
gland;  the  nervi  erigentes  in  the  erection  of  the  penis,  clitoris,  etc.;  and 
the  nerves  to  the  erectile  tissue  of  the  nasal  fossae. 

Sympathetic  Afferent  Neurons. — It  is  known  that  sympathetic 
afferent  fibers  with  their  cell  bodies  located  in  the  geniculate  ganglion 
are  constituents  of  the  pars  intermedia  of  the  facial  nerve.  Doubtless 
the  peripheral  processes  of  some  of  these  neurons  accompany  and  are  apart 
of  the  great  superficial  petrosal  nerve  and  pass  through  thesphenopalatine 
or  nasal  ganglion  of  Meckel  to  be  distributed  by  way  oi  the  branches 
of  the  ganglion  to  the  mucous  membrane  of  the  nasal  fossa,  the  paranasal 
sinuses,  and  the  neighboring  parts.  The  central  processes  of  the  genic- 
ulate sympathetic  cell  bodies  follow  the  trunk  of  the  pars  intermedia  of  the 
facial  nerve  into  the  medulla  oblongata  and  while  their  central  connections 
are  not  clearly  established  they  presumably  form  additional  synapse 
relations,  either  directly  or  indirectly,  (i)  with  the  vasoconstrictor  center 
in  the  medulla;  (2)  with  the  vasodilator  centers  (particularly  the  centers 
of  dilator  fibers  which  accompany  the  pars  intermedia  of  the  facial,  the 
glossopharyngeal  and  the  cervical  sympathetic),  probably  located  vari- 
ously in  the  medulla;  (3)  with  the  cardio-inhibitory  center  in  the  medulla; 
and  (4)  with  somatic  efferent  neurons  of  the  head  and  cervical  regions. 


290  THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 

Additional  sympathetic  afferent  fibers  from  the  nasal  cavity  and 
sinuses  seemingly  reach  the  spinal  cord  by  way  of  the  cervical  sympathetic 
cord,  with  cell  bodies  located  in  the  ganglia  of  the  dorsal  roots  of  the 
upper  thoracic  nerves.  The  central  processes  of  these  cell  bodies  establish 
additional  synapse  relations  with  efferent  sympathetic  (preganglionic) 
and  efferent  somatic  neurons  within  the  spinal  cord. 

The  relations  formed  between  afferent  or  sensory  sympathetic 
neurons  and  efferent  somatic  and  sympathetic  neurons  establish  neuron 
arcs  for  reflexes.  Moreover,  afferent  sympathetic  neurons  from  the  nose 
synapse  either  directly  or  indirectly  (by  intercalation  of  additional  ele- 
ments) with  the  cell  bodies  of  somatic  sensory  neurons  located  in  the  ganglia 
on  the  dorsal  roots  of  the  upper  thoracic  spinal  nerves  and  in  thegeniculate 
ganglion.  The  synapse  relations  between  afferent  sympathetic  and 
afferent  somatic  neurons  provide  the  mechanism  for  the  transfer  of  sym- 
pathetic sensory  impulses  to  the  somatic  sensory  system  (see  page  302). 

The  Vasoconstrictor  Center. — The  vasoconstrictor  center  is  located 
in  the  medulla  oblongata  (bulb)  and  is  always  in  tonic  activity.  The  cell 
bodies  of  the  center  give  off  axons  which  descend  in  the  spinal  cord  and 
terminate  at  various  levels  in  the  ventral  (motor)  horn  of  gray  matter, 
from  the  first  thoracic  to  the  second  or  third  lumbar  spinal  nerves.  Here 
they  synapse  with  the  cell  bodies  of  the  preganglionic1  (efferent)  sym- 
pathetic neurons.  The  cell  bodies  of  the  vasoconstrictor  center  with  their 
axons  form,  therefore,  central  or  intercalary  neurons  of  the  vasocon- 
strictor pathway. 

The  Vasodilator  Center.— That  vasodilator  fibers  exist  for  the  supply 
of  erectile  tissue,  glands  and  muscles  is  established  beyond  peradventure. 
These  fibers  are,  however,  not  connected  centrally,  so  far  as  the  evidence 
tends  to  show,  with  a  single  center.  Presumably  the  dilator  fibers  in 
the  pars  intermedia  of  the  facial,  the  glossopharyngeal,  and  the  cervi- 
cal sympathetic  have  their  cell  bodies  located  variously  in  the  medulla. 
Additional  vasodilator  centers  are,  doubtless,  present  in  the  spinal  cord. 
Physiologic  evidence  tends  to  show  that  the  vasodilator  fibers  are  not  in 
tonic  activity  as  are  the  vasoconstrictor  fibers.  From  the  anatomic 
arrangement  of  the  pale  muscle  fibers  in  the  walls  of  blood-vessels,  it 
would  seem  that  the  vasodilators  when  stimulated  bring  about  turgescence 
of  a  vascular  area  (dilatation  of  the  vessels)  by  inhibiting  the  tonic  action 
of  the  vasoconstrictors. 

1  Recent  experimentation  seems  to  indicate  that  in  the  thoracic  segments  of  the  spinal  cord  the  cell 
bodies  of  the  preganglionic  neurons  may  under  some  conditions  function  as  subordinate  vasoconstric- 
tor centers  capable  of  tonic  and  reflex  activity. 


REFLEX  CIRCUITS  291 

C.  REFLEX  CIRCUITS 

The  anatomic  relationships  of  neurons  within  the  correlation  centers 
mentioned  in  the  foregoing  paragraphs  complete  reflex  circuits  or  arcs, 
composed  of  receptors,  adjusters,  and  effectors.  Moreover  the  circuits 
provide  afferent  (somatic  sensory  neurons  of  trigeminal  nerve  and  sym- 
pathetic sensory  neurons)  and  efferent  (somatic  motor  neurons  of  various 
cranial  nerves,  somatic  motor  neurons  of  the  upper  spinal  nerves,  and 
sympathetic  motor  neurons  of  the  cranial  and  thoracolumbar  outflows) 
conductors  or  pathways,  whereby  the  adjusters  or  correlation  centers  are 
brought  into  physiologic  relations  with  the  receptors  (sense  organs)  and 
effectors  (response  organs) .  These  several  components  of  the  neuron  arc 
or  circuit  provide  the  anatomic  mechanism  for  reflex  phenomena  that 
follow  adequate  stimulation  of  the  general  afferent  fibers  of  the  trigeminal 
nerve  and  seemingly  of  sympathetic  afferent  fibers  that  borrow  the  branches 
of  the  trigeminal  nerve  as  pathways  for  a  greater  or  less  distance  in  their 
course  to  the  central  axis. 

It  is  not  deemed  profitable  nor  essential  in  this  connection  to  speak 
of  the  anatomic  arcs  for  the  divers  simple  and  complex  reflex  acts  and 
phenomena  that  take  place  following  adequate  stimulation1  of  the  recep- 
tors or  sense  organs  located  within  the  nasal  mucous  membrane  and  re- 
lated parts.  A  single  reference  will  suffice  to  point  out  the  general  prin- 
ciples involved. 

When,  for  example,  the  normal  unanesthetized  mucous  membrane 
is  stimulated  with  an  applicator  brush,  or  an  irritant  gas  is  inhaled,  there 
follows  immediately  and  before  consciousness  can  be  a  factor  a  reflex 
twitching  of  the  facial  muscles,  movements  of  the  eyeball,  a  movement  of 
the  head  to  one  side,  and  an  elevation  of  the  arm  in  an  effort  to  remove  the 
offending  brush  or  gas.  Furthermore,  a  careful  examination  will  show 
that  the  blood-vascular  network  within  the  nasal  mucous  membrane  has 
undergone  a  dilatation  or  turgescence,  to  be  followed  by  an  increased 
secretion  of  watery  fluid  from  the  glands  of  the  mucous  membrane; 
indicating  a  stimulation  of  the  vasodilator  and  secretomotor  centers, 
whereby  the  tonic  effect  of  the  vasoconstrictor  center  is  reflexly  inhibited. 
Sneezing  not  infrequently  follows.  The  intensity  of  the  reactions  is  in 
direct  accord  with  the  degree  of  stimulation.  The  reflex  movements 
of  the  striped  muscles  of  the  face,  neck,  arm,  etc.,  are  due  to  the  central 

1  It  must  be  recalled  that  receptors  respond  only  when  the  stimulus  is  sufficiently  strong  and  of 
the  proper  sort — degree  of  intensity  and  kind  is,  therefore,  the  adequate  stimulus.  Arthur  F.  Hertz 
has  shown  that  "a  nerve-ending  maybe  sensitive  to  one  form  of  stimulation — the  adequate  stimulus — 
but  insensitive  to  all  others."  The  Sensibility  of  the  Alimentary  Canal,  London,  1911. 


292  THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 

connections  between  the  somatic  sensory  neurons  of  the  trigeminal  nerve 
and  the  somatic  motor  neurons1  of  various  cranial  and  spinal  nerves. 
The  reflex  movements  of  these  can,  of  course,  be  voluntarily  inhibited, 
controlled  or  modified,  since  the  opposite  pyramidal  tract  (corticopontine, 
corticobulbar,  corticospinal  fibers)  gives  collaterals  and  terminals  to  the 
nuclei  of  the  several  motor  cranial  nerves  and  to  the  ventral  (motor)  horn 
cells  of  the  spinal  cord. 

The  sneezing,  however,  cannot  be  voluntarily  controlled,  neither  can 
it  be  voluntarily  performed.  The  afferent  channels  are  the  internal 
nasal  branches  of  the  trigeminus  and  at  times  the  olfactory  (the  latter 
in  case  of  intense  odors).  The  efferent  or  motor  paths  lie  in  the  nerves  of 
the  muscles  of  expiration.  In  the  correlation  center  connecting  neurons 
are  interposed.  While  sneezing  cannot  be  performed  voluntarily,  it  may 
be  inhibited  by  compressing  the  medial  nasal  nerve  below  the  septum 
mobile  nasi.  Here  we  have  the  operation  of  antagonistic  reflexes — the 
reflex  incident  to  the  compression  of  the  medial  nasal  nerve  (of  the  ophthal- 
mic division  of  the  trigeminus)  overcoming  or  inhibiting  the  reflex  of 
sneezing  incident  to  stimulation  of  the  neives  in  the  interior  of  the  nose 
(of  the  maxillary  division  of  the  trigeminus). 

Moreover,  the  control  of  the  nasal  congestion  and  glandular  activity 
are  not  under  the  power  of  the  will  since  unstriped  or  pale  muscle  and 
glands  are  involved.  It  is  well  known  that  the  central  processes  of  the 
cell  bodies  of  the  sympathetic  afferent  neurons  synapse  with  either  somatic 
or  sympathetic  efferent  or  motor  neurons  within  the  central  nervous  sys- 
tem in  the  completion  of  reflex  arcs.  Experimental  evidence  tends  also 
to  show  that  afferent  somatic  neurons,  in  addition  to  completing  reflex 
arcs  with  efferent  somatic  neurons,  participate  in  the  formation  of  reflex 
arcs  in  which  the  efferents  are  of  the  sympathetic  type.  It  is,  therefore, 
possible  that  an  impulse  from  the  nasal  cavity  meant  primarily  to  bring 
about  reflexly  a  pure  motor  response  of  striated  muscles  results  in  a  vaso- 
motor  phenomenon  as  well,  e.g.,  turgescence  of  the  erectile  tissues  of  the 
nose.  It  is  obviously  difficult  to  determine  whether  the  afferent  impulse 
from  the  nose  reached  the  central  nervous  system  by  way  of  sympathetic 
sensory  or  somatic  sensory  neurons,  owing  to  the  intimate  anatomic  rela- 

xThe  efferent  neurons  of  the  trigeminal,  facial,  glossopharyngeal,  vagus  and  accessory  nerves 
supplying  striated  muscles  in  the  head  and  neck  are  often  referred  to  as  special  visceral  efferent 
(motor)  neurons,  since  the  muscles  they  supply  are  derived  from  the  unsegmented  mesoderm  and 
not  from  the  early  mesodermal  segments — the  source  of  the  somatic  striated  muscles.  It  must, 
however,  be  understood  that  the  facial,  mandibular,  hyoid,  laryngeal  and  pharyngeal  muscles  are 
striated  and  are  under  the  control  of  the  will  and  that  their  nerve  endings  are  like  those  of  the 
striated  muscles  of  the  somatic  series  proper. 


REFLEX  NASAL  MANIFESTATIONS  293 

tionships  that  are  established,  whereby  transfer  of  sensory  impulses  from 
the  sympathetic  to  the  somatic  system  is  continually  made.  However, 
the  trigeminal  nerve  is  obviously  the  important  afferent  pathway. 

It  must,  however,  be  recalled  that,  even  though  the  turgescence  and 
depletion  of  the  nasal  mucosa  is  commonly  a  simple  reflex  phenomenon, 
under  certain  conditions  the  erectile  tissue  of  the  nose  is  readily  influenced 
by  psychic  states,  indicating  a  connection  between  the  vasomotor  centers 
and  the  cerebral  cortex.  Indeed,  intracentral  efferent  neurons  from  the 
cortex  to  the  vasomotor  reflex  centers  have  been  demonstrated.  More- 
over, while  it  is  true  that  the  exteroceptive  arcs  are  most  closely  connected 
with  the  skeletal  musculature  and  the  interoceptive  with  the  visceral,  and 
that  seemingly  some  resistance  to  conduction  from  one  to  the  other  exists, 
the  fact  remains,  nevertheless,  that  the  unstriped  muscle  of  the  blood- 
vascular  areas  is  readily  influenced  by  stimulating  either  the  interoceptive 
or  the  exteroceptive  fields.1 

Turgescence  of  the  cavernous  tissue  of  the  nasal  mucous  membrane 
is  essentially  a  vasodilator  phenomenon,  just  as  Eckhard  has  shown  for 
the  erection  of  the  penis  and  clitoris,  and  is  due  either  to  a  reflex  excitation 
of  the  vasodilator  centers  and  fibers  or  to  a  reflex  inhibition  of  the  tonic 
activity  of  the  vasoconstrictor  center.  If  the  latter,  one  sees  how  the 
nasal  mucosa  would  become  depleted  after  a  temporary  congestion,  by  a 
removal  of  the  inhibition  and  an  assertion  of  the  tonic  action  of  the 
vasoconstrictor  center  and  fibers,  whereby  the  size  of  the  vascular  areas 
becomes  lessened.  It  is  obvious  that  psychic  states  play  an  important 
role  in  the  stimulation  of  the  vasodilator  centers — blushing  of  the  face 
from  emotions,  congestion  of  the  salivary  glands  on  thinking  of  an  appe- 
tizing food,  the  erection  of  the  cavernous  tissues  of  the  male  and  female 
genitalia  in  erotic  states  of  mind  are  common  examples. 

Reflex  Nasal  Manifestations  Incident  to  Nasal  Disease  and  Dis- 
orders.— The  reflex  circuits  or  arcs  provide  also  the  anatomic  and  physio- 
logic mechanisms  for  the  many  and  varied  reflex  manifestations  that  are 
encountered  clinically  in  diseases  of  the  nose  and  paranasal  (accessory) 
sinuses  and  in  malpositions  of  nasal  parts.  Pure  nasal  neuroses  are 
not  as  common  as  one  time  believed.  Careful  study  and  examination 
in  many  instances  reveal  the  source  of  the  reflex.  It  is,  of  course,  obvious 
that  adequate  and  suitable  stimulation  of  the  sense  organs  of  the  normal 
nasal  fossae  and  sinuses  will,  in  some  instances  at  least,  result  in  reflex 
nasal  manifestations  not  unlike  those  encountered  in  nasal  disease,  etc. 
Some  of  the  so-called  reflex  nasal  manifestations  incident  to  nasal  dis- 

1  Charles  S.  Sherrington:  The  Integrative  Action  of  the  Nervous  System,  New  Haven,  1916. 


294  THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 

orders  and  those  of  neighboring  parts  are  in  reality  of  a  referred  nature 
and  should  not  be  thought  of  as  reflexes  (pages  302  and  305). 

Many  of  the  reflex  nasal  manifestations  are  puzzling  from  an 
anatomico-physiological  viewpoint  and  much  work  needs  to  be  done  to 
clear  the  obscure  horizon.  Indeed,  further  study  may  show  that  anatomy 
and  physiology  have  no  adequate  explanation  for  some  of  them.  However, 
in  spite  of  some  obscure  conditions,  there  are  many  reflex  and  referred 
nasal  manifestations  that  occur  in  nasal  diseases  that  can  be  accounted 
for  by  the  anatomic  arrangements  and  relations  of  neurons  composing 
neuron  circuits,  and  unless  these  pathways  are  kept  in  mind  and  clearly 
understood  faulty  interpretations  will  be  given  many  of  these  reflex 
and  referred  phenomena  which  emanate  from  the  nose,  the  paranasal 
sinuses  and  the  related  parts. 

It  is  not  the  province  here  to  enter  into  a  discussion  of  the  many 
reflex  nasal  manifestations  and  neuroses.  The  reader  is  referred  to 
treatises  on  clinical  neurology  and  rhinology  for  detailed  expositions 
concerning  them.  The  reflex  and  referred  manifestations  encountered 
in  nasal  disease  can  in  a  general  way  be  divided  into  motor,  sensory, 
trophic,  and  vasomotor.  In  relation  with  the  respiratory  tract  one  meets 
with  such  important  conditions  as  sneezing,  coughing  and  asthma,  which 
are  directly  traceable  to  nasal  disorders.  Reflex  phenomena  in  the  ear 
referable  to  nasal  disease  are  not  uncommon.  Lacrimation  due  to  tur- 
gescence  of  the  inferior  nasal  concha  has  been  reported.  Migraine  and 
neuralgias  may  be  referred  manifestations  due  to  conchal  lesions,  sinus 
disease,  septal  spurs,  etc.  Gastralgia,  indigestion  and  vomiting  have 
been  recorded  as  produced  reflexly  by  intranasal  disease.  Alteration  of 
the  cardiac  rhythm  and  numerous  sexual  phenomena  frequently  have  a 
definite  nasal  reference.  The  reverse  may  also  be  true,  e.g.,  nasal  phe- 
nomena have  a  definite  sexual  origin. 

One  naturally  wonders  how,  for  example,  the  cardiac  rhythm  can  be 
affected  by  nasal  disease  and  by  suitable  or  adequate  stimulation  other- 
wise applied  to  the  interior  of  the  nose.  It  has  been  demonstrated  that 
experimental  irritation  of  certain  portions  of  the  nasal  mucous  membrane 
results  in  an  alteration  of  the  heart  beat.  Moreover,  it  has  been  reported 
that  some  typical  cases  of  so-called  cardiac  neuroses  and  arhythmias  were 
cured  by  the  treatment  of  hypertrophied  nasal  conchae  and  deflected 
nasal  septa.  It  is  necessary  in  this  connection  to  recall  (i)  that  afferent 
impulses  from  the  nose  pass  over  the  trigeminal  fibers  (somatic  sensory 
neurons)  to  the  terminal  trigeminal  nucleus,  thence  by  way  of  the  centrally 
directed  trigeminothalamic  tract  to  the  thalamus  and  from  there  to  the 


REFLEX  PATHS 


295 


somesthetic  area  of  the  cortex  for  the  conscious  recognition  of  such 
impulses  (some  impulses  may  pass  via  sympathetic  afferent  fibers  over 
the  peripheral  branches  of  the  trigeminal,  the  great  superficial  petrosal 
and  the  pars  intermedia  of  the  facial),  and  (2)  that  nasal  impulses  may 
follow  reflex  axons  from  the  nucleus  of  termination  of  the  trigeminal  nerve 
and  collaterals  from  the  trigeminothalamic  tract  to  the  dorsal  nucleus 
of  the  vagus  nerve  (nucleus  of  the  ala  cinerea)  located  in  the  medulla  and 
which  contains  the  cardio-inhibitory  center.  In  all  probability  connec- 
tions are  also  established  with  the  predominant  cardio-accelerator  center 
located  in  the  medulla  and  secondary  cardio-accelerator  centers  of  the 
high  thoracic  cord. 

The  inhibitory  preganglionic  neurons  (sympathetic  motor)  to  the 
heart  represent  a  component  part  of  the  outflow  of  the  medulla  or  bulbar 
sympathetic  fibers,  the  cell  bodies  of  which  are  located,  as  stated  above, 
in  the  dorsal  nucleus  of  the  vagus  nerve,  and  the  peripheral  fibers  (axons) 
are  distributed  by  way  of  the  trunk  of  the  vagus.  The  peripheral  fibers 
end  by  synapsing  with  sympathetic  ganglion  cells,  located  within  or  near 
the  heart,  of  cardio-inhibitory  postganglionic  neurons  destined  for  the 
supply  of  the  heart  muscle.  The  preganglionic  accelerator  neurons  to  the 
heart  emerge  from  the  spinal  cord  in  the  ventral  roots  of  the  first,  second, 
third  and  fourth  thoracic  spinal  nerves.  The  cardio-accelerator  center, 
probably  located  in  the  medulla,  establishes  synapse  relationships  with 
the  cell  bodies  of  the  preganglionic  accelerator  fibers  located  in  the  ventral 
horn  of  the  spinal  cord.  It  is,  therefore,  obvious  that  the  heart  beat  which 
is  inhibited  by  the  bulbar  sympathetic  (visceral)  system  through  the  vagus 
nerve  and  accelerated  by  the  thoracolumbar  sympathetic  system  through 
certain  thoracic  spinal  nerves,  can  be  reflexly  influenced  by  adequate 
afferent  stimuli  of  nasal  origin.  This,  since  neuron  pathways  are  provided 
not  only  for  the  possible  conscious  recognition  of  the  sensory  impulses, 
but  also  pathways  whereby  the  somatic  sensory  and  the  sympathetic 
afferent  impulses  are  carried  to  the  correlation  or  adjuster  centers  and 
from  there  sympathetic  efferent  impulses  to  the  heart  muscle. 

Since  the  nucleus  ambiguus  contains  the  cell  bodies  of  origin  of  the 
somatic  efferent  or  motor  fibers  of  the  vagus  nerve1  which  supply  the  cross 
striated  muscles  of  the  pharynx  and  larynx  there  is  a  reason  for  the  so- 
called  nasal  cough  (reflex  cough)  in  disorders  of  the  nasal  fossa,  and  since 
the  opposite  pyramidal  tract  gives  terminals  and  collaterals  to  the  nucleus 

1  Probably  the  glossopharyngeal  nerve  receives  efferent  fibers  from  the  nucleus  ambiguus. 
Cunningham,  however,  questions  whether  this  nerve  contains  any  motor  fibers  at  all,  there  being 
paths  by  which  the  fibers  of  its  so-called  motor  branch  to  the  stylopharyngeus  muscle  might  enter 
the  nerve  from  sources  other  than  the  nucleus  ambiguus. 


296  THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 

ambiguus  for  the  movements  of  the  larynx  and  pharynx  the  cough  may 
be  voluntarily  controlled  unless  the  nasal  stimulation,  owing  to  diseased 
states,  is  excessive  and  the  resultant  reflex  cough  beyond  the  control  of 
the  will. 

Most  of  the  cerebrospinal  control  of  the  visceral  reactions  is  effected 
from  the  sympathetic  centers  located  in  the  medulla  by  way  of  the  vagus 
nerve.  Sympathetic  efferent  (preganglionic)  fibers  with  cell  bodies 
located  in  the  dorsal  nucleus  of  the  vagus  are  distributed  by  the  vagus 
to  various  sympathetic  ganglia.  From  the  latter  go  forth  postganglionic 
neurons  for  the  supply  of  such  organs  as  the  esophagus,  the  stomach,  the 
small  intestines,  the  lungs,  the  heart  (inhibitory,  referred  to  above), 
etc.  These  connections  account  for  such  reflex  manifestations  as 
asthma,  gastralgia  and  vomiting  in  nasal  diseases.  It  is  well  known,  for 
example,  that  the  removal  of  nasal  polypi  or  the  exenteration  of  the  eth- 
moid labyrinth  in  severe  ethmoiditis  have  effected  cures  of  troublesome  and 
vague  asthmas.  Moreover,  the  relationship  between  the  nose  and  attacks 
of  bronchial  asthma  has  also  been  established  experimentally.  Weak 
electrical  currents  applied  to  the  nasal  mucous  membrane  increase  the 
intrabronchial  pressure  (Lazarus).1  Stimulation  of  the  nasal  septum 
produces  spasm  of  the  muscular  walls  of  the  smaller  bronchioles  (Brodie 
and  Dixie).2 

Naso-sexual  Relations. — The  wide  connections  between  the  cortical 
olfactory  centers  and  other  parts  of  the  cerebrum  provide  anatomic  and 
physiologic  mechanisms  for  the  many  associations  connected  with  odors. 
Moreover,  it  is  obvious  from  daily  observations  and  experiences  that  in 
many  animals  (man  included,  although  to  a  less  degree)  the  olfactory 
sense  is  very  intimately  connected  with  sexual  reflexes. 

Apart  from  the  peripheral  and  central  olfactory  organs  there  appears 
to  exist  a  definite  physiologic  and  pathologic  relationship  between  the 
nose  and  paranasal  sinuses  and  the  sexual  organs.  Certain  sexual  condi- 
tions seem  to  have  a  nasal  reference  and  vice  versa,  e.g.,  some  nasal  dis- 
orders seemingly  are  the  result  of  sexual  irritation  or  disease.  Indeed, 
there  are  some  striking  anatomic  and  physiologic  analogies  between  cer- 
tain portions  of  the  sexual  organs  and  the  nose.  Menstrual  life  may  be 
established  by  the  occurrence  of  nasal  bleeding.  Turgescence  of  the 
erectile  tissue  of  the  nasal  fossae  may  regularly  accompany  menstruation  in 
women  with  normal  nasal  mucous  membranes.  Nose-bleed  is  frequent  in 
boys  at  the  age  of  puberty.  The  symptoms  of  nasal  diseases  are  not  in- 

1  Deut.  Med.  Woch.,  XVII,  1891. 

2  Trans.  Path.  Soc.,  London,  LIV,  1903. 


NASO-SEXUAL  RELATIONS  297 

frequently  aggravated  during  the  menstrual  period  and  following  sexual 
excesses.  Indeed,  sexual  excesses  in  some  instances  appear  to  be  the 
cause  of  certain  nasal  disorders.  Moreover,  reflex  sneezing,  engorgement 
of  the  nasal  erectile  tissue,  coryza,  hypertrophic  changes  in  the  nasal 
fossae  have  been  reported  as  concomitants  of  sexual  excesses.  Elsberg 
some  years  ago  suggested  that  arrested  sexual  development  might  be  due 
to  nasal  disease.  Schiff  stimulated  the  noses  of  female  dogs  and  found 
that  in  7  out  of  15  animals  experimented  upon  contractions  of  the  uterus 
followed  the  nasal  irritation.  Control  stimulations  of  the  sciatic  nerve 
gave  feeble  uterine  responses.  Priapism  due  to  nasal  disorders  is  not  un- 
known, cures  having  followed  nasal  treatment.  Certain  dysmenorrheas 
are  believed  by  some  clinicians  to  have  a  definite  nasal  reference. 

Many  of  the  so-called  naso-sexual  relations  are  obscure.  Probably 
some  have  a  phylogenetic  bearing.  Others  may  be  merely  the  expression 
of  a  more  or  less  uniform  reaction  of  anatomically  similar  tissues,  e.g., 
erectile  or  cavernous  tissues.  Pure  neuroses  are  doubtless  encountered. 
However,  certain  of  the  naso-sexual  relations,  when  carefully  studied, 
seem  to  be  of  a  reflex  nature  with  the  source  of  the  reflexes  located  either 
in  the  genital  apparatus  or  in  the  nasal  cavity.  The  cause  of  such  reflexes 
may  be  due  to  diseased  states  or  adequate  stimuli  otherwise  applied.  In 
this  connection  a  knowledge  of  the  established  neuron  arcs  or  circuits 
is  essential.  As  stated  previously,  asthmas,  coughs,  vomiting,  alterations 
of  cardiac  rhythm,  etc.,  are  frequently  reflex  expressions  of  nasal  stimu- 
lation incident  to  disease,  etc.  For  these  manifestations  the  neuron 
pathways  are  more  or  less  definite  and  established.  It  is,  therefore, 
plausible  and  indeed  probable  that  nasal  stimulation  if  of  the  proper  sort 
will  reflexly  influence  the  sexual  apparatus  (exclusive  of  the  obvious  influ- 
ence of  the  olfactory  sense  on  the  sexual  reflexes).  Indeed,  laboratory 
experimentation  a  ad  clinical  evidence  lend  support  to  the  thesis.  Un- 
fortunately the  neuron  arcs  or  circuits  are  not  as  well  known  in  this  con- 
nection as  elsewhere.  However,  some  outstanding  facts  are  unmistak- 
able. It  is  obviously  difficult  to  establish  certain  links  in  some  neuron 
circuits  (reflex  circuits)  and  until  this  is  done  it  is  justifiable  and  proper 
to  assume  tentatively  certain  facts  based  on  established  related  facts  and 
clinical  evidence  and  experience.  One  must,  however,  remember  that 
some  of  the  reported  cures  of  reflex  manifestations  in  patients  following 
treatment  of  the  nose  or  sexual  apparatus  mean  nothing  more  nor  less 
than  suggestion  and  mental  influence  on  the  part  of  the  patient  and  want 
of  discriminate  judgment  on  the  part  of  the  physician.  It  is  not  deemed 
profitable  in  this  connection  to  discuss  the  many  and  varied  observations 


298  THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 

reported  in  the  literature,  suffice  it  to  speak  of  a  few  conditions  in  which 
nasal  irritation  seemingly  gives  rise  to  reflex  genital  expression,  with  spe- 
cial reference  to  probable  neuron  circuits. 

Priapism  is  according  to  some  apparently  authentic  cases  occasionally 
caused  reflexly  by  nasal  disease.  The  removal  of  the  nasal  irritant 
with  a  concomitant  cure  of  the  priapism  seems  to  establish  the  nasal 
source  of  the  reflex.  In  this  connection  one  must,  however,  always  bear 
in  mind  that  intermittent  priapism  is  not  infrequently  seen  in  neurasthenic 
men  subjected  to  prolonged  mental  strain  and  that  the  cure  of  the  priapism 
following  nasal  treatment  may  be  merely  a  mental  suggestion.  In  spite 
of  the  fact  that  in  the  vast  majority  of  cases  priapism  is  an  expression 
of  spinal  lesions,  etc.  (see  proper  treatises  on  the  subject),  the  nasal 
fossae  as  a  possible  source  of  the  reflex  seems  established.  One  naturally 
wonders,  however,  what  the  possible  underlying  anatomic  and  physio- 
logic mechanism  of  the  relationship  can  be.  Despite  the  relative  un- 
importance of  this  relationship,  it  may  not  be  amiss  to  briefly  survey 
neuron  pathways  and  centers  that  may  possibly  be  involved  in  this  and 
other  connections. 

Persistent  abnormal  erection  of  the  penis,  usually  without  sexual 
desire  (priapism),  like  the  normal  erection  of  the  penis  is  a  vasodilator 
phenomenon.  Normal  erection  is  a  reflex  act  effected  through  a  secondary 
center  in  the  lumbar  cord.  This  center  may  be  aroused  by  psychic 
impulses  descending  from  the  brain  (erotic  sensations,  for  example) 
or  reflexly  by  sensory  (afferent)  impulses  arising  in  the  genital  tract 
and  elsewhere.  Persistent  (at  times  intermittent)  abnormal  erection 
or  priapism  is  likewise  clearly  a  reflex  act  and  doubtless  effected  through 
the  same  secondary  erector  center  in  the  lower  portion  of  the  spinal  cord. 
The  center  may  be  aroused  by  afferent  impulses  incident  to  pathologic 
conditions  of  the  genital  tract — for  example,  gonorrhea;  or  by  afferent 
impulses  arising  from  pathologic  states  in  more  remote  parts  of  the  body — 
for  example,  the  nasal  fossae  (priapism  due  to  spinal  cord  and  blood 
conditions  do  not  concern  us  here). 

The  sacral  efferent  sympathetic  fibers  (preganglionic)  make  their 
exit  from  the  spinal  cord  with  the  ventral  roots  of  the  second,  third  and 
fourth  sacral  nerves.  These  sympathetic  fibers  become  massed  in  the 
pelvis  and  form  the  nervus  erigens  (pelvic  nerve),  which  terminates  about 
cell  bodies  of  sympathetic  ganglia  located  in  the  hypogastric  or  pelvic 
plexuses.  From  the  cell  bodies  of  these  ganglia  go  forth  fibers  (post- 
ganglionic)  for  the  supply  of  the  pelvic  viscera.  Some  of  these  fibers  are 
vasodilator  in  function  to  the  vessels  of  the  pelvic  organs  and  the  external 


NASO-SEXUAL  RELATIONS  299 

genitalia.  Stimulation  of  the  pudendal  nerve  or  of  the  nervus  erigens 
results  in  a  turgescence  or  erection  of  the  erectile  tissues  of  the  penis, 
clitoris,  etc. ;  seemingly  by  inhibiting  the  vasoconstrictor  fibers  which 
arise  from  the  second  to  the  fifth  lumbar  segments  of  the  spinal  cord  and 
pass  as  preganglionic  fibers  to  the  inferior  mesenteric  ganglion.  From 
the  latter  issue,  among  others,  postganglionic  vasoconstrictor  fibers  which 
course  by  way  of  the  hypogastric  (sympathetic  nerve)  and  plexus  and 
the  pudendal  nerve  (internal  pudic  nerve)  to  the  erectile  tissues  of  the 
penis,  clitoris,  etc. 

There  is  strong  evidence  that  the  dominating  vasodilator  center  is 
located  in  the  medulla  with  subordinate  centers  in  the  spinal  cord;  for 
example,  the  erection  center  in  the  lumbar  region.  The  dominating 
vasodilator  center  is  connected  by  descending  fibers  with  the  cell  bodies 
of  preganglionic  neurons  issuing  from  the  subordinate  erection  center. 
As  stated  before,  stimulation  of  the  nervi  erigentes  leads  to  erection  of 
the  penis,  and  the  erectile  genital  tissues  of  the  female.  Moreover,  ir- 
ritation of  the  glans  penis,  clitoris,  etc.,  leads  to  erection  even  after  the 
lumbar  cord  is  severed  from  the  remaining  portion  of  the  cerebrospinal 
axis.  This  indicates  that  the  afferent  impulses  pass  over  the  pudendal 
nerve,  moreover,  that  the  subordinate  center  can  function  independently 
of  the  dominating  center.  Eckhard1  found  that  erection  of  the  penis 
can  be  produced  by  stimulation  of  the  spinal  cord,  of  the  medulla,  and  of 
the  pons  as  far  as  the  peduncles.  This  may  explain  the  phenomenon 
of  priapism  in  spinal  cord  and  brain  stem  lesions.  It  has  been  shown  also 
that  the  psychical  activity  of  the  cerebral  cortex  has  a  profound  influence 
on  the  vasodilator  nerves  of  the  sexual  apparatus.  Indeed,  Pussep2 
has  shown  that  electrical  stimulation  of  a  definite  field  of  the  cerebral 
cortex  leads  to  penile  erection  and  ejaculation  in  dogs.  It  is,  therefore, 
obvious  that  the  subordinate  vasodilator  (erection)  center  in  the  lumbar 
region  can  be  directly  stimulated  reflexly  by  irritation  of  the  genital 
system.  Moreover,  it  is  equally  clear  that  the  dominant  vasodilator 
center  exercises  some  sort  of  control  over  the  subordinate  center  by  way 
of  the  neuron  connections.  Since  the  trigeminal  nerve  (carrying  afferent 
impulses  from  the  nose,  etc.)  establishes  relationships  through  inter- 
calated neurons  with  somatic  and  sympathetic  efferent  neurons  (of  various 
motor  cranial  nerves  and  of  the  upper  spinal  nerves),  it  is  highly  probable 
that  similar  relationships  are  established  with  the  dominant  vasodilator 
center  probably  located  in  the  medulla.  And,  as  stated  above,  the  domi- 

1  Eckhard,  Beitrage  zur  Anatomic  und  Physiologic,  1863  and  1869. 

2  Hermann's  Jahresbericht  der  Physiologic,  Vol.  XL,  1903. 


300  THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 

nant  and  subordinate  vasodilator  (erection)  centers  are  connected.  This 
would  establish  a  complete  neuron  arc  (or  better,  circuit)  from  the  nasal 
cavity  to  the  erectile  tissue  of  the  genital  apparatus,  thereby  providing 
an  anatomic  mechanism  for  the  causation  of  priapism  incident  to  nasal 
disorders. 

Fleiss  in  1895  an<i  I^971  called  the  attention  of  rhinologists  and  gyne- 
cologists to  what  he  considered  an  important  relationship  between  certain 
areas  of  the  nasal  mucous  membrane  and  the  female  genitalia  and  adnexa. 
He  found  when  applying  a  20  per  cent,  solution  of  cocaine  to  an  exceed- 
ingly small  area  of  mucous  membrane  on  the  tuberculum  septi,  directly 
opposite  the  mid-portion  of  the  middle  nasal  concha,  and  to  the  mucous 
membrane  over  the  ventral  portion  of  the  inferior  nasal  concha  that  pains  in 
the  back  and  abdomen  incident  to  dysmenorrhea  ceased  after  five-  to 
eight-minute  applications  and  did  not  return  until  the  effect  of  the  drug  had 
disappeared.  Moreover,  Fleiss  claimed  that  if  the  anterior  portion  of  the 
inferior  concha  on  eitrfer  side  of  the  nose  was  touched  the  headache  ceased, 
but  had  no  effect  on  the  abdominal  pains.  If  one  side  of  the  nose  was 
treated  with  a  20  per  cent,  solution  of  cocaine,  applied  to  both  of  the  spots, 
the  headache  and  the  pain  on  the  opposite  side  of  the  abdomen  was  re- 
lieved. To  obtain  a  definite  cure  of  the  dysmenorrhea  it  sufficed,  according 
to  Fleiss,  to  destroy  the  nasal  areas  in  question  with  the  galvano-cautery. 
Because  of  their  apparent  connection  with  the  genitalia  and  adnexa 
Fleiss  designated  these  areas  of  the  nasal  mucosa  the  genital  spots. 

Since  the  initial  reports  by  Fleiss  a  number  of  rhinologists  and  gyne- 
cologists have  treated  dysmenorrhea  with  cocaine,  trichloracetic  acid, 
menthol  and  the  actual  cautery  by  way  of  the  so-called  genital  spots,  with 
very  divergent  results.  Some  confirm  the  findings  of  Fleiss,  others  find 
the  treatment  efficacious  in  a  selected  type  of  cases,  while  a  third  group 
of  clinicians  consider  the  treatment  of  dysmenorrhea  by  way  of  the  nasal 
mucosa  irrational,  and  when  found  "effective"  to  be  merely  the  imagina- 
tion of  the  patient  and  the  physician. 

Anatomically,  as  stated  elsewhere,  the  nasal  mucous  membrane  is 
divided  into  the  olfactory  and  the  respiratory  portions,  the  former  con- 
taining the  perceptive  olfactory  elements.  The  respiratory  portion  over 
the  inferior  nasal  concha,  a  goodly  portion  of  the  middle  nasal  concha  and 
the  adjacent  portion  of  the  nasal  septum  is  distinctly  cavernous  in  its 
structure  and  assumes  the  role  of  an  erectile  tissue.  Further  study  may 
point  to  the  erectile-tissue  portion  of  the  nasal  mucous  membrane  as  most 

1  Wien.  Klin.  Rundschau,  1895.  The  Relation  of  the  Nose  and  Female  Genitalia,  Leipsig, 
Vienna,  1897. 


NASO-SEXUAL  RELATIONS 


301 


intimately  related  with  the  genitalia  and  adnexa.  This  area  of  the  nasal 
mucosa  is,  however,  much  more  extensive  than  the  genital  spots  of  Fleiss. 
As  stated  on  page  272,  the  "genital  spots"  do  not  present  histologic  char- 
acteristics that  particularize  them  from  the  erectile-tissue  portion  of 
the  nasal  mucous  membrane. 

It  would  appear  from  various  experiments  and  observations  that  the 
pelvic  sexual  organs  are  reflexly  influenced  from  divers  sources.  The 
uterus,  for  example,  contracts  reflexly  on  stimulating  the  central  end  of 
the  sciatic  nerve  (Basch  and  Hofmann),  the  central  end  of  the  brachial 
plexus  (Schlesinger),  the  nose  (Schiff),  the  nipple  (Scanzoni).  Linder  in 
a  number  of  laparotomies  observed  contraction  of  the  uterus  following 
irritation  of  the  nasal  mucosa  corresponding  essentially  to  the  distribution 
of  the  nasal  cavernous  tissue.  Spiegelberg  found  that  stimulation  of 
the  lumbar  and  sacral  parts  of  the  spinal  cord  caused  powerful  uterine 
movements.  The  observation  has  also  been  made  that  stimulation  of  the 
sciatic  nerve  results  in  reflex  stimulation  of  the  vasoconstrictor  fibers  of 
the  uterus.  Now  comes  the  contention  that  certain  types  of  dysmenor- 
rhea,  doubtless  meaning  more  than  merely  a  uterine  congestion,  have  a 
nasal  reference.  In  general,  the  pelvic  field  is  supplied  by  vasoconstrictor 
nerves  by  way  of  the  hypogastric  nerve  and  plexus  (pre-  and  postganglionic 
neurons)  from  the  last  thoracic  and  upper  lumbar  segments  of  the  cord 
and  by  vasodilator  fibers  through  the  nervi  erigentes  and  their  postgan- 
glionic connections. 

Stevens  in  French's  Index  of  Differential  Diagnosis  classes  dysmenor- 
rheas  into  three  basic  types — spasmodic,  congestive  and  membranous — 
and  gives  a  number  of  causes  for  the  several  types.  He  holds  that  spas- 
modic cases  are  practically  always  primary,  that  is,  they  commence  with 
the  onset  of  menstruation;  while  congestive  and  membranous  types  are 
secondary,  that  is,  acquired  as  a  result  of  some  definite  lesion.  There  is, 
however,  no  conformity  in  treatises  on  gynecology  on  the  subject  of  dys- 
menorrhea,  this  applying  equally  to  classification,  etiology  and  treatment. 

The  relation  of  the  nose  to  dysmenorrhea  is  extremely  obscure  and 
certainly  not  established  at  the  present  time  despite  the  iact  that  many 
very  suggestive  clinical  observations  have  been  made.  In  some  of  the 
congestive  types  of  dysmenorrhea,  if  there  be  such,  nasal  disease  or  dis- 
orders may  possibly  be  a  lactor  in  reflexly  stimulating  the  vasodilator 
centers  of  the  genital  apparatus,  and  at  the  time  of  menstruation  (indeed, 
for  some  time  before)  lead  to  a  hypercongestion  of  the  extensive  vascular 
network  of  the  pelvic  genitalia.  It  is,  likewise,  possible  to  conceive  that 
nasal  treatment  might  reflexly  stimulate  the  vasoconstrictor  center,  thus 


302  THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 

leading  to  a  general  lessening  of  the  congestion  by  a  constriction  of  the 
blood-vessels.  Depletion  of  the  congested  areas  would  lessen  the  pressure 
on  the  nerves,  thereby  influencing  the  pain.  Moreover,  the  permanent 
removal  of  the  pathologic  state  in  the  nose,  which  reflexly  resulted  in 
pelvic  congestion  by  inhibiting  the  peripheral  tonic  activity  of  the  vaso- 
constrictor nerves,  would  permit  the  vasoconstrictor  mechanism  to  assume 
its  usual  and  normal  tonic  activity;  whereby,  owing  to  the  reduced  caliber 
of  the  blood-vessels,  the  amount  of  blood  in  the  vascular  channels  would  be 
lessened. 

If  the  trigeminus  nerve,  through  reflex  neurons  in  the  medulla,  estab- 
lishes synapse  relations  with  the  vasoconstrictor  and  the  vasodilator 
centers,  thereby  bringing  about  reflex  nasal  phenomena,  etc.,  one  naturally 
wonders  why  adequate  stimulation  of  the  trigeminal  nerve  should  not  at 
times  result  in  reflex  pelvic  phenomena,  since  the  connections  of  the  vaso- 
motor  centers  in  the  medulla  with  related  secondary  centers  in  the  lower 
portions  of  the  spinal  cord  are  fairly  well  established.  The  connections 
of  the  secondary  vasoconstrictor  centers  (lumbar  cord)  and  the  vasodilator 
centers  (sacral  cord)  with  the  intrapelvic  and  extrapelvic  genitals  are 
discussed  elsewhere. 

The  Transference  and  Reference  of  Afferent  (Sensory)  Impulses. — 
The  class  of  so-called  reflex  pains  are,  correctly  speaking,  transferred  and 
referred  sensations  since  there  is  no  reflex  action  involved  in  the  process. 
So  far  as  the  transference  and  reference  of  pain  is  concerned  in  which 
the  nose,  paranasal  sinuses  and  related  parts  are  at  fault,  two  sets  of  nerves 
require  attention:  (i)  the  afferent  nasal  distribution  of  the  trigeminal 
nerve  and  (2)  the  afferent  nasal  sympathetics. 

i.  One  or  other  of  the  divisions  of  the  trigeminal  nerve  is  commonly 
involved  in  referred  pain.  Indeed,  such  pains  may  include  the  entire 
distribution  of  the  nerve.  In  general,  diffusion  of  pain  over  the  sensory 
trigeminal  system  is  at  first  confined  to  the  division  supplying  the  offend- 
ing or  diseased  area,  and  as  the  pain  impulse  gains  in  severity  there  is  an 
overflow  and  reference  along  the  other  main  divisions  of  the  nerve. 

Dental  caries,  for  example,  while  at  first  giving  rise  to  a  more  or  less 
local  pain,  may,  if  a  marked  case  of  nerve  exposure  and  irritation  exists, 
lead  to  such  general  reference  of  pain  along  the  various  branches  of  the 
trigeminal  nerve  that  it  is  impossible  for  the  patient  to  locate  the  source 
of  the  trouble.  Extraction  of  a  wrong  and  healthy  tooth  is  a  well-known 
error  of  commission  in  such  cases.  Pain  in  the  ear  due  to  a  carious  tooth 
of  the  mandible  or  lower  jaw  is  of  frequent  occurrence  and  for  its  proper 
interpretation  a  knowledge  of  the  composition  and  distribution  of  the 


TRANSFERRED  AND  REFERRED  IMPULSES  303 

mandibular  nerve  (n.  mandibularis,  inferior  maxillary  nerve)  is  essential. 
It  is  of  interest  in  this  connection  to  note  the  anatomic  communication 
between  the  inferior  alveolar  (dental)  nerve  and  the  auriculotemporal 
nerve.  The  auriculotemporal  nerve  of  the  mandibular  division  frequently 
refers  a  pain  impulse  coming  over  the  lingual  nerve  of  the  same  division 
to  the  ear  and  the  temporal  fossa.  This  is  particularly  true  in  ulceration 
and  cancer  of  the  tongue.  Indeed,  in  the  latter  malady  such  reference 
of  pain  may  precede  the  appreciation  of  local  pain.  Neuralgias  of  the 
maxillary  nerve  (n.  maxillaris)  are  common  in  connection  with  caries  of 
the  upper  teeth,  maxillary  sinus  disease,  medial  and  lateral  nasal  wall 
disorders. 

Some  of  the  worst  supraorbital  pains  are  due  to  disease  of  the  frontal 
sinus  and  the  ethmoid  labyrinth  and  are  referred  along  branches  of  the 
ophthalmic  nerve  (n.  ophthalmicus). 

It  should  also  be  recalled  that  the  pars  intermedia  of  the  facial  nerve 
contains  a  number  of  somatic  sensory  neurons,  some  of  which  are  for  gen- 
eral sensation  and  course  by  way  of  the  great  superficial  petrosal  nerve, 
the  nerve  of  the  pterygoid  canal  (Vidian  nerve),  the  sphenopalatine  gang- 
lion and  the  small  and  middle  palatine  nerves  to  be  distributed  to  the 
soft  palate  and  adjacent  portions  of  the  pharynx.  It  is  conceivable  that 
-  these  nerves  (peripheral  processes)  with  cell  bodies  in  the  geniculate 
ganglion  in  their  way  centrally  through  or  around  the  sphenopalatine 
ganglion  would  be  irritated  in  disease  of  the  latter  and  thereby  account 
for  the  referred  pharyngeal  pain  (sore  throat)  in  pure  sphenopalative 
involvement. 

2.  Sympathetic  afferent  (sensory)  fibers  from  the  environs  of  the  nose 
seemingly  synapse,  as  stated  elsewhere,  either  directly  by  collaterals  or 
indirectly  by  intercalation  of  an  additional  neuron  with  the  cell  bodies 
ot  the  somatic  sensory  neurons  located  in  the  ganglia  of  the  dorsal  roots 
of  the  upper  thoracic  spinal  nerves.  Similar  relationships  of  sympathetic 
and  somatic  sensory  paths  are  also  probably  established  within  the  genic- 
ulate ganglion.  Such  synapse  relations  are  well  established  for  the  dorsal 
ganglia  of  typical  spinal  nerves.  Moreover,  Herrick  believes  that  colloca- 
tions of  sympathetic  and  somatic  sensory  paths  similar  to  those  in  the 
ganglia  of  the  dorsal  roots  of  the  spinal  nerves  exist  within  the  spinal 
cord  and  brain.  By  such  anatomic  arrangement  or  mechanism,  sym- 
pathetic sensory  impulses  from  the  nasal  mucous  membrane  would  be 
transferred  from  the  sympathetic  sensory  system  to  the  related  somatic 
sensory  system  for  sensorial  (cortical)  stimulation;  and  since  the  functions 
of  the  sympathetic  nerves  in  general  do  not  come  into  consciousness  the 


304  THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 

transferred  sympathetic  sensory  impulses  may  be  referred  by  the  brain 
as  pain  to  the  peripheral  field  of  distribution  of  the  associated  somatic 
nerves  and  thus  brought  into  consciousness.  It  is  well  known  that 
pathologic  conditions  of  certain  organs  or  areas  may  be  accompanied  not 
by  pain  at  the  site  of  the  disease,  but  by  cutaneous  pain  and  tenderness 
in  more  remote  parts  of  the  body  (Fig.  194^4). 

Indeed,  such  Deference  of  pain  occurs  in  some  nasal  disorders.  A 
striking  example  apparently  is  found  in  an  involvement  of  the  spheno- 
palatine  or  nasal  ganglion  of  Meckel.  Sluder1  has  reported  that  in  these 
cases  there  is  pain  in  the  root  of  the  nose  and  in  and  about  the  eye,  the 
upper  jaw  and  teeth,  sometimes  the  lower  jaw  and  teeth,  the  mastoid  re- 
gion, the  ear,  and  in  severe  cases  pain  extending  to  the  neck,  shoulder, 
breast,  arm,  forearm,  hand  and  fingers;  also  a  sense  of  sore  throat  on  the 
same  side.  In  this  connection  one  must  recall  the  distribution  of  the 
cranial  nerves  coming  from  the  medulla  and  the  pons  and  the  composition 
and  distribution  of  the  brachial  and  cervical  plexuses  in  order  that  trans- 
ferred and  referred  manifestations  may  be  properly  interpreted. 

It  is  obviously  difficult  to  determine  in  disease  of  the  sphenopalatine 
ganglion  whether  the  afferent  impulses  to  the  central  nervous  system 
are  by  way  of  afferent  sympathetic  or  afferent  somatic  neurons. 
Since  the  peripheral  processes  of  both  the  sympathetic  and  somatic 
sensory  neurons  utilize  the  ganglion  in  question  as  a  pathway,  it  would 
seem  plausible  that  both  systems  of  nerves  must  be  involved  and  convey 
impulses  from  the  diseased  ganglion.  In  all  probability,  however,  most  of 
the  pains  mentioned  above  associated  with  disease  of  the  sphenopalatine  gang- 
lion are  in  reality  an  expression  of  irritation  of  peripheral  fibers  of  the  tri- 
geminal  nerve  which  pass  via  the  ganglion  in  their  course  centrally.  Overflow 
of  the  afferent  sensations  would  cause  them  to  be  referred  along  certain 
other  peripheral  trigeminal  fibers  and  probably  along  other  nerves  with 
which  the  latter  establish  peripheral  communications. 

There  are,  however,  according  to  Sluder,  pains  referred  to  regions  far 
removed  from  the  field  of  distribution  of  the  trigeminal  nerve  and  remote 
from  the  nasal  fossae  and  paranasal  sinuses  in  some  of  the  severer  cases  of 
sphenopalatine  ganglion  involvement.  This  would  appear  to  indicate 
that  both  sympathetic  and  somatic  afferents  were  involved  in  the  mechan- 
ism of  some  of  the  referred  pains  in  question. 

1  Greenfield  Sluder:  Further  Clinical  Observations  on  the  Sphenopalatine  Ganglion  (Motor, 
Sensory,  Gustatory),  New  York  Med.  Jour.,  1910. 

The  Syndrome  of  the  Sphenopalatine  Ganglion  Neurosis,  Tr.  Am.  Laryngol.  Assn.,  1910. 

The  Sympathetic  Syndrome  of  Sphenopalatine  (Nasal)  Ganglion  Neurosis,  Together  with  the 
Consideration  of  the  Neuralgic  Syndrome  and  Their  Treatment,  Tr.  Am.  Laryngol.  Assn.,  1915. 


TRANSFERRED  AND  REFERRED  IMPULSES  305 

It  is  well  known  that  sympathetic  afferent  neurons  are  among 
the  constituents  of  the  pars  intermedia  of  the  facial  nerve.  The  peripheral 
processes  of  some  of  these  follow  the  great  superficial  petrosal  nerve,  the 
nerve  of  the  pterygoid  canal  (Vidian  nerve)  to  the  sphenopalatine  ganglion. 
They  pass  either  around  or  through  the  latter  to  be  distributed  with  the 
ganglionic  branches.  Moreover,  somatic  afferents  are  likewise  found  in 
the  pars  intermedia,  some  of  which  follow  the  same  course  mentioned 
for  the  sympathetic  afferents.  In  both  instances  the  cell  bodies  of  the 
neurons  are  located  in  the  geniculate  ganglion  where  synapse  relations 
by  collaterals  are  •  presumably  established  between  the  sympathetic  and 
somatic  elements.  The  transferred  impulse  may  then  be  referred  to  the 


PIG.  1944. — A  schematic  representation  of  the  synapse  relations  in  a  spinal  ganglion  whereby 
afferent  visceral  sensations  are  transferred  from  the  sympathetic  system  to  the  somatic  sensory 
system.  The  afferent  visceral  sensations  do  not  come  into  consciousness  as  such  but  pass  to  the 
brain  over  afferent  somatic  paths;  the  brain  not  infreqeuntly  interpreting  them  as  pain  and  referring 
them  to  the  peripheral  field  of  distribution  of  the  related  somatic  nerves,  giving  rise  to  referred 
pain. 

I  =  Cell  of  Dogiel;  2  =  Afferent  somatic  neurons;  3  =  Afferent  sympathetic  neuron  with  cell 
body  located  within  the  spinal  ganglion;  4  =  Afferent  sympathetic  neuron  with  cell  body  located  in 
a  sympathetic  ganglion;  g,  =  spinal  ganglion;  pn,  =  peripheral  nerve;  re,  =  ramus  communicans. 

peripheral  endings  of  the  somatic  sensory  neurons  by  the  brain  and  inter- 
preted as  pain.  This  may  explain  certain  pharyngeal  pains  in  involve- 
ment of  the  sphenopalatine  ganglion  (see  also  page  315). 

It  is  also  probable,  from  the  clinical  evidence  at  hand,  that  sympa- 
thetic afferent  neurons  with  cell  bodies  located  in  the  ganglia  on  the 
dorsal  roots  of  the  upper  four  thoracic  spinal  nerves  send  some  of  their 
peripheral  processes  (in  a  sense  dendrites)  to  the  nasal  and  adjacent 
fields  by  way  of  the  cervical  sympathetic  cord,  the  great  deep  petrosal 
nerve,  the  nerve  of  the  pterygoid  canal  (Vidian  nerve),  the  sphenopalatine 
ganglion  and  its  branches.  In  these  spinal  ganglia  synapse  relations 


306  THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 

are  presumably  established  between  the  sympathetic  afferent  neurons 
and  the  somatic  sensory  neurons,  and  doubtless  here  some  transfer  of  sym- 
pathetic impulses  is  made  to  the  somatic  sensory  neurons  as  well  as  some 
impulses  carried  into  the  cord  over  the  axonic  piocesses  of  the  sympa- 
thetic cell  bodies  of  the  dorsal  spinal  ganglia  for  reflex  arc  connections 
with  both  sympathetic  and  somatic  efferents  (Fig.  194^!). 

Since  the  first  and  second  thoracic  nerves  participate  in  the  formation 
of  the  brachial  plexus  and  the  latter  distributed  to  the  shoulder,  upper 
extremity,  etc.;  moreover,  since  sympathetic  afferent  impulses  do  not 
come  into  consciousness,  save  possibly  in  an  extremely  vague  fashion, 
the  brain  naturally  refers  or  interprets  the  sympathetic  sensory  impulses 
as  pain  and  coming  from  the  somatic  sensory  nerves  of  the  fingers,  hand, 
arm,  shoulder,  etc.,  to  which  the  initial  impulses  from  the  diseased  spheno- 
palatine  ganglion  have  been  transferred.1 

Herrick's  observation,2  that  collocations  similar  to  those  occurring 
in  the  spinal  ganglia  between  the  sympathetic  and  somatic  sensory  paths 
are  undoubtedly  established  within  the  spinal  cord  and  brain,  probably 
offers  the  solution  for  referred  pains  in  those  regions  where  the  necessary 
peripheral  anatomic  mechanisms  for  the  transfer  of  sympathetic  afferent 
impulses  to  the  somatic  afferent  pathways  are  wanting  or,  if  existent,  are 
unknown. 

D.  THE  PERIPHERAL  NERVES  AND  THE  SPHENOPALATINE  GANGLION 

The  Maxillary  Division  of  the  Trigeminal  Nerve  in  its  Nasal  Dis- 
tribution.— The  maxillary  nerve  (n.  maxillaris)  leaves  the  cranial  cavity 
through  the  foramen  rotundum,  traverses  the  pterygopalatine  (spheno- 
maxillary)  fossa  and  enters  the  orbital  cavity  by  way  of  the  inferior 
orbital  (sphenomaxillary)  fissure.  Once  in  the  orbit  the  maxillary  nerve  is 
known  as  the  infraorbital  nerve  and  courses  ventralward  in  the  floor 
of  the  orbital  cavity,  traversing  the  infraorbital  sulcus  and  the  infra- 
orbital  canal,  finally  emerging  on  the  face  through  the  infraorbital  foramen. 
In  its  course  through  the  infraorbital  sulcus  and  canal,  the  infraorbital 
nerve  comes  into  intimate  relationship  with  the  roof  or  orbital  wall  of  the 
maxillary  sinus  (Fig.  198).  Indeed,  there  may  be  dehiscences  in  the  cau- 
dal surface  of  the  sulcus  and  the  canal  so  that  the  nerve  comes  into  actual 

1  Postscript:  Since  the  completion  of  the  manuscript  of  the  foregoing  discussions,  Dr.  Green- 
field Sluder's  book  on  "Headaches  and  Eye  Disorders  of  Nasal  Origin,"  St.  Louis,  1918,  has  appeared 
The  reader  is  referred  to  this  splendid  work  for  many  anatomico-clinical  observations  on  the  spheno- 
palatine  ganglion  and  the  paranasal  sinuses. 

2  Loc.  cit. 


MAXILLARY  NERVE  IN  ITS  NASAL  SUPPLY  307 

contact  with  the  mucous  membrane  of  the  sinus  for  a  greater  or  less 
distance. 

The  sphenopalatine  nerves  (nn.  sphenopalatini)  or  the  so-called  sen- 
sory roots  to  the  sphenopalatine  ganglion  of  Meckel  leave  the  maxillary 
nerve  in  the  pterygopalatine  fossa  as  two  or  three  short,  stout  trunks.  Con- 
trary to  what  one  is  led  to  believe  from  a  gross  dissection,  an  exceedingly 
small  portion  of  the  sphenopalatine  nerves  enter  the  sphenopalatine  gang- 
lion, the  larger  portion  passing  on  the  lateral  or  ventral  surface  of  the  gang- 

Bulbus  ojfactori.us 
M tthsnoidali*  ant. 


.  palatvu 


, 

\     tfn.Ttasales  pastcrions 
\     Mi.nasales  postcn'orcs  supcrfores  lot. 
Mpalatinus  anterior 
;    JY.  palalifuis  mceUus 
MpaZatinus  posterior 


FIG.  195.  —  The  nerves  of  the  lateral  wall  of  the  nasal  fossa.  The  nerves  of  both  the  olfactory 
and  respiratory  portions  of  the  fossa  are  shown.  Note  the  Vidian  nerve  in  the  floor  of  the  sphenoidal 
sinus  and  the  osseous  dehiscence  at  y  with  exposure  of  the  maxillary  nerve  to  the  sinus  mucosa.  An- 
other osseous  dehiscence  at  x  exposes  the  internal  carotid  artery,  which  forms  a  serpentine-like 
mound  on  the  lateral  wall  of  the  sphenoidal  sinus.  The  inset  shows  the  dissection  of  the  cavernous 
dural  sinus  with  contained  structures. 

lion  to  continue  as  the  greater  bulk  of  the  fibers  of  the  so-called  branches  of 
the  ganglion.  The  few  sensory  or  sphenopalatine  nerve  fibers  that  termi- 
nate in  the  ganglion  supply  the  capsule  of  the  latter  and  convey  impulses 
of  general  sensibility  from  the  ganglion  in  question  to  the  central  nervous 
system  (Fig.  201,  neuron  No.  3).  The  bulk  of  the  fibers  that  do  enter  and 


308 


THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 


terminate  in  the  sphenopalatine  ganglion  are  the  axons  of  the  pre- 
ganglionic  (sympathetic)  neurons  (motor  and  secretory)  contributed  by 
various  nerves  and  which  synapse  with  (arborize  with)  postganglionic 
(sympathetic)  neurons  within  the  ganglion,  and  which  latter  are  destined 
for  the  supply  of  unstriped  or  involuntary  muscle  and  glands  located  in  the 
nose  and  related  parts.  The  axons  of  the  latter  neurons,  together  with 
the  sphenopalatine  nerve  fibers  which  pass  on  the  surface  of  the  spheno- 


ant.inadiales  Sinus 

N.  ethmoidal.is  anter/oris    ..    ;  Chiasma. 

Kit.  olfactoru,    :  /  Hypophysis 


iwisivus  JVeru 

FIG.   196. — The  nerves  of  the  medial  or  septal  wall  of  the  nasal  fossa. 


palatine  ganglion,  conjointly  form  the  conventional  branches  of  the  sphe- 
nopalatine ganglion;  the  branches  containing  a  few  fibers  of  cell  bodies 
located  in  Meckel's  ganglion  and  a  far  greater  number  with  cell  bodies 
located  in  the  Gasserian  ganglion.  A  variable  number  of  nerve  fibers 
whose  cell  bodies  are  located  in  the  geniculate  ganglion  likewise  course 
by  way  of  the  sphenopalatine  ganglion  and  certain  of  its  distributing 
branches.  Strictly  speaking,  therefore,  the  "branches"  of  Meckel's 


MAXILLARY  NERVE  IN  ITS  NASAL  SUPPLY  309 

ganglion  are  direct  continuations  of  the  sphenopalatine  branches  of  the 
maxillary  nerve,  augmented  by  a  variable  number  of  peripheral  processes 
(axons)  of  postganglionic  (sympathetic)  neurons  with  cell  bodies  located 
within  the  sphenopalatine  ganglion  and  of  peripheral  processes  of  afferent 
sympathetic  and  somatic  neurons  with  cell  bodies  located  in  the  geniculate 
ganglion,  etc. 

Cc.etkTTwidaJes    ant. _,  ,...  Sinus  frontalis 

Cc.ethmMdcdcs   post.  s  /         -r> 

i    r~  Proc.  zuxinatv,s 


A.carotis  inter 'tut. 
N,ocuZo motor -ln,s 


flf.canalis  ptvryy( 
Recessit^  phttry, 

FIG.    197. — A  regional  dissection  of  a  midsagittal  section  of  an  adult  head.     Particularly  note  the 
nerve  relations  of  the  sphenoidal  sinus. 

The  following  nerves,  usually  mentioned  as  branches  of  the  spheno- 
palatine ganglion,  supply  both  the  medial  and  lateral  walls  of  the  nasal 
fossa  from  a  line  erected  from  the  incisive  foramen  to  the  dorsal  third 
of  the  cribriform  plate  dorsalward  to  the  choanae : 

The  orbital  rami  (rami  orbitales)  are  two  or  three  thread-like  ascending 
branches  which  pass  into  the  orbit  through  the  inferior  orbital  fissure 
(sphenomaxillary  fissure)  into  the  orbital  cavity  and  after  traversing 
the  posterior  ethmoidal  foramen,  or  a  special  foramen,  are  distributed  to 
the  posterior  ethmoidal  cells  and  the  sphenoidal  sinus. 


310  THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 

The  palatine  nerves  (nervi  palatini)  are  descending  branches  and 
are  usually  described  under  three  heads:  (a)  The  anterior  palatine  nerve 
(nervus  palatinus  anterior,  the  large  posterior  palatine  nerve)  passes 
through  the  large  posterior  palatine  foramen  to  reach  the  inferior  surface 
of  the  hard  palate,  then  courses  forward  in  a  groove' in  the  hard  palate  and 
arborizes  with  the  nasopalatine  nerve  (which  see) .  Moreover,  the  anterior 
palatine  nerve,  in  its  course  through  the  large  posterior  palatine  foramen, 
gives  off  a  variable  number  of  posterior  inferior  nasal  rami  (rr.  nasales 
posteriores  inferiores).  The  latter  pass  through  the  small  apertures  in 
the  perpendicular  plate  of  the  palate  bone  and  supply  the  mucoperiosteum 
of  the  dorsal  half  of  the  inferior  nasal  concha  and  the  adjacent  portions  of 
the  middle  and  inferior  nasal  meatuses.  (b)  The  middle  palatine  nerves 
(nervi  palatini  mediae,  the  accessory  posterior  palatine  nerves)  pass  through 
the  small  palatine  foramen  and  supply  the  mucosa  of  the  soft  palate  and  the 
faucial  tonsillar  region,  (c)  The  posterior  palatine  nerve  (nervus  palatinus 
posterior,  the  small  posterior  palatine  nerve)  descends  in  a  small  posterior 
palatine  foramen  to  supply  the  inferior  surface  of  the  soft  palate.  Probably 
the  facial  nerve  sends  aberrant  fibers  over  the  posterior  palatine  nerve  for  the 
motor  supply  of  the  levator  palati  and  the  azygos  uvulae  muscles  (Fig.  95). 

The  posterior  superior  nasal  rami  (rami  nasales  posteriores  superiores) 
are  internal  branches  from  the  sphenopalatine  ganglion.  They  pass 
from  the  pterygopalatine  (sphenomaxillary)  fossa  through  the  spheno- 
palatine foramen  into  the  nasal  fossa.  Once  in  the  nasal  fossa  the  fila- 
ments composing  the  nerves  assemble  themselves  into  two  groups:  (a) 
rami  laterales,  (b)  rami  mediales.  The  lateral  rami  (the  posterior  superior 
nasal  nerve)  supply  the  mucous  membrane  of  all  the  structures  entering 
into  the  dorsocephalic  portion  of  the  lateral  wall  of  the  nasal  fossa.  The 
medial  rami  cross  the  dorsal  portion  of  the  roof  of  the  nasal  fossa  to  reach 
the  mucosa  of  the  septal  wall  which  they  supply.  Once  in  the  septal 
mucosa  the  main  trunk  of  the  medial  rami  (nervus  nasopalatinus,  Scarpae) 
passes  ventrocaudalward  in  a  groove  in  the  vomer  and  septal  cartilage 
to  reach  the  Y-shaped  incisive  or  anterior  palatine  foramen  through  which 
with  its  fellow  of  the  opposite  side  it  passes  and  forms  a  fine  plexus.  On 
the  caudal  surface  the  nasopalatine  nerves  arborize  with  the  anterior 
palatine  nerves  (vide  supra).  The  nasopalatine  nerve  and  the  related 
medial  rami  supply  branches  to  the  dorsal  portion  of  the  nasal  roof,  the 
nasal  septum,  and  the  portion  of  the  hard  palate  derived  from  the  pal- 
atine processes  of  the  maxillae  (Figs.  195  and  196). 

The  posterior  superior  alveolar  rami  (posterior  superior  dental 
nerves),  usually  two,  arise  from  the  maxillary  nerve  before  the  latter  be- 


MAXILLARY  NERVE  IN  ITS  NASAL  SUPPLY  311 

comes  the  infraorbital,  pass  caudally  and  ventrally  upon  the  infratemporal 
surface  of  the  maxilla,  sooner  or  later  entering  the  alveolar  canals  to  pass 
to  the  molar  teeth  and  to  participate  in  the  formation  of  the  superior 
dental  plexus.  In  some  cases  the  nerves  pass  under  cover  of  the  mucosa 
of  the  maxillary  sinus  (Fig.  198). 

The  middle  superior  alveolar  ramus  (middle  superior  dental  nerve) 
arises  from  the  infraorbital  nerve  in  the  proximal  part  of  the  infraorbital 
canal.  It  courses  caudalward  in  a  canal  in  the  lateral  wall  of  the  maxil- 


Nn.  alveolarcs  superiors^  posterioivs 
\          N.  infraorbitulis 

N.  alveolaris  superior  mtdius 


r tf.infruorbitalis 

;  Hn.alvcolares  super iores  antcriorcs 


FIG.    198.— A  dissection  showing  the  maxillary  and  infraorbital  nerves  and  branches  as  related  to  the 

maxillary  sinus. 

lary  sinus  and  after  entering  into  the  formation  of  the  superior  dental 
plexus  supplies  the  premolar  teeth.  It  may  arise  from  the  anterior  superior 
alveolar  nerve  (vide  infra)  (Fig.  198). 

The  anterior  superior  alveolar  ramus  (anterior  superior  dental  nerve) 
arises  from  the  infraorbital  nerve  immediately  proximal  to  the  infra- 
orbital  foramen.  The  nerve  usually  descends  in  a  canal  in  the  ventral  or 
facial  surface  of  the  maxillary  sinus.  It  aids  in  the  formation  of  the  su- 


3I2 


THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 


perior  dental  plexus  and  supplies  the  canine  and  incisor  teeth.  Occasion- 
ally the  anterior  superior  alveolar  arises  from  the  infraorbital  nerve  farther 
dorsad  than  usual,  passes  through  the  caudal  wall  of  the  infraorbital  canal 
and  courses  diagonally  from  the  roof  to  the  ventral  wall  of  the  maxillary 
sinus  under  cover  of  the  mucous  membrane.  Indeed,  at  times  the  mucosa 
is  drawn  away  from  the  bone  so  that  the  nerve  is  suspended  by  mucous 
membrane  and  in  a  sense  is  in  the  maxillary  sinus  (Figs.  198  and 
199). 

The  anterior  superior  alveolar  nerve  gives  off  a  nasal  branch  which 
enters  the  nasal  fossa  through  a  small  canal  in  the  lateral  wall  of  the  in- 
ferior nasal  meatus  to  supply  the  mucoperiosteum  of  the  ventral  portion 


FIG.  199.— A  dissection  showing  the  anterior  superior  alveolar  nerve  (N)  issuing  from  the  infra- 
orbital  nerve  some  distance  behind  the  infraorbital  foramen  and  coursing  under  cover  of  the  mucous 
membrane  of  the  maxillary  sinus  (see  text). 

N    =   N.  alveolar  superioris  anterioris;  Nni    =    Nn.  infraorbitales;  Rp  =  Recessus  prelacrimalis 
(sinus  maxillaris). 

of  the  under  surface  of  the  inferior  concha,  also  the  corresponding  portion 
of  the  inferior  meatus  and  the  fossal  floor. 

The  maxillary  floor  receives  filaments  from  the  superior  alveolar 
(dental)  nerves  in  their  course  and  additional  filaments  from  the  superior 
dental  plexus. 

The  infraorbital  nerve  after  its  emergence  from  the  infraorbital  canal 
breaks  up  into  a  large  tuft-like  mass  of  terminal  branches;  the  external 
nasal  rami  (rami  nasales  externi),  some  of  which  supply  the  lateral  sur- 
face of  the  external  nose,  particularly  the  ala  nasi;  and  the  internal  nasal 
rami  (rami  nasales  interni),  some  of  which  supply  the  septum  mobile  nasi. 


OPHTHALMIC  XKRYK  IX  ITS  XASAL  SUPPLY  313 

The  Ophthalmic  Division  of  the  Trigeminal  Nerve  in  its  Nasal 
Distribution.— The  nasociliary  (nasal)  nerve,  one  of  the  three  main 
branches  of  the  ophthalmic  nerve,  originally  erroneously  supposed  by 
Magendie  to  be  the  nerve  of  smell,  but  subsequently  accurately  interpreted 
by  Eschricht,  enters  the  orbit  through  the  superior  orbital  (sphenoidal) 
fissure,  between  the  heads  of  the  lateral  rectus  muscle  and  between  the 
two  divisions  of  the  oculomotor  nerve.  The  nerve  then  courses  obliquely 
across  the  orbital  cavity  to  reach  the  anterior  ethmoidal  foramen  located 
on  the  ventromedial  surface  of  the  orbit.  The  main  portion  of  the  naso- 
ciliary nerve  traverses  the  foramen  as  the  anterior  ethmoidal  nerve  (nervus 
ethmoidalis  anterior)  and  passes  into  the  cranial  cavity,  then  courses 
forward  along  the  cranial  surface  of  the  cribriform  plate  of  the  ethmoid 
bone  to  the  nasal  fissure  at  the  side  of  the  crista  galli  through  which  it 
passes  into  the  nasal  fossa. 


Cdlin  crista,  galli  x  Sinus  froritaLis 


BulbvA  ol factoring ' '  Jfecess  expansion  of  S.fronfalis 


FIG.   200. — A  transaction  through  the  frontal  sinus  and  the  crista  galli.     Note  the  cell  in  the  latter 
and  the  encroachment  of  the  frontal  sinuses  on  the  confines  of  the  olfactory  bulbs. 

Before  the  nasociliary  nerve  reaches  the  anterior  ethmoidal  foramen, 
it  frequently  gives  off  a  branch,  the  posterior  ethmoidal  nerve,  which 
traverses  the  posterior  ethmoidal  foramen  on  the  dorsomedial  aspect  of 
the  orbital  cavity  to  supply  the  mucous  membrane  of  the  posterior  eth- 
moidal cells  and  the  sphenoidal  sinus.  Moreover,  the  anterior  ethmoidal 
nerve  gives  off  filaments  as  it  traverses  the  anterior  ethmoidal  foramen 
for  the  supply  of  the  anterior  ethmoidal  cells  and  the  frontal  sinus.  Once 
in  the  nasal  fossa  the  anterior  ethmoidal  nerve  terminates  as  such  by 
dividing  into  the  medial  and  lateral  nasal  branches — the  rami  nasales 
mediates  and  the  rami  nasales  later  ales,  respectively.  The  medial  rami 
(septal  branches)  supply  the  mucous  membrane  of  the  ventral  portion 
of  the  nasal  septum  nearly  as  far  as  the  naris.  The  lateral  rami  (lateral 
nasal  nerve)  are  represented  by  two  or  three  filaments  and  are  distributed 
to  the  mucous  membrane  of  the  ventral  portion  of  the  lateral  wall  of  the 


3 14  THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 

nasal  fossa,  including  the  ventral  portions  of  the  middle  and  inferior  nasal 
conchae.  Moreover,  a  branch  of  the  lateral  rami  or  lateral  nasal  nerve 
continues  as  the  ramus  nasalis  externus  (external  nasal  branch)  by  groov- 
ing the  deep  surface  of  the  nasal  bone  and  issuing  from  between  the  nasal 
bone  and  the  lateral  cartilage  of  the  nose.  It  then  courses  caudalward 
under  cover  of  the  compressor  naris  muscle  to  the  tip  of  the  nose  and 
supplies  the  integument  over  the  lower  half  and  tip  of  the1  external  nose. 
As  the  nasociliary  nerve  nears  the  anterior  ethmoidal  foramen,  it  gives 
off  the  infratrochlear  nerve  (n.  infratrochlearis)  which  passes  forward  along 
the  medial  wall  of  the  orbital  cavity  below  the  superior  oblique  muscle 
to  the  medial  commissure  of  the  palpebral  fissure  where  it  ends  in  filaments 
which  supply  the  conjunctiva,  the  lacrimal  sac  and  caruncle,  the  integu- 
ment of  the  upper  eyelid,  and  the  root  and  lateral  aspect  of  the  nose  as 
far  as  the  lateral  nasal  cartilage  (Figs.  195  and  196). 

The  Sphenopalatine  Ganglion. — The  sphenopalatine  ganglion  (g. 
sphenopalatinum),  also  known  as  Meckel's,  the  nasal  or  the  sphenomaxil- 
lary  ganglion,  is  a  small  triangular,  reddish-gray  (in  the  fresh  state)  body 
and  is  a  component  of  the  group  of  sympathetic  ganglia  found  in  the  head 
region  of  the  body.  It  is  located  in  the  sphenopalatine  fossa  and  very 
close  to  the  sphenopalatine  foramen  and  is  suspended  from  the  maxillary 
division  of  the  trigeminal  nerve.  The  sphenopalatine  ganglion  is,  there- 
fore, more  or  less  intimately  related  topographically  with  the  lateral  wall 
of  the  nasal  fossa,  the  sphenoidal  sinus  and  certain  of  the  posterior  eth- 
moidal cells.  In  its  histologic  make-up  it  consists  of  an  interlacement  of 
nerve  fibers  and  stellate  nerve  cell  bodies.  The  nerve  fibers,  forming 
the  ganglionic  branches  (see  pages  306  1031 1),  participate  in  supplying  the 
nasal  fossa  and  the  related  parts. 

In  conformity  with  the  other  sympathetic  ganglia  of  the  head  the 
sphenopalatine  or  nasal  ganglion  has  three  so-called  roots  which  convey 
nerve  fibers  to  and  from  the  ganglion;  e.g.,  motor  (visceral  motor),  sensory 
and  sympathetic.  Strictly  speaking,  it  is  a  mere  convention  to  designate 
the  roots  as  motor,  sensory  and  sympathetic  respectively  since  they  usually 
are  of  a  mixed  character  as  regards  the  physiology  of  their  component 
nerve  fibers.  However,  one  or  other  type  of  fibers  usually  predominates 
in  the  several  roots,  a  fact  that  probably  justifies  the  naming  of  the  roots 
as  has  been  done. 

The  motor  root  of  the  sphenopalatine  ganglion  in  its  major  part  con- 
sists of  visceral  (sympathetic)  motor  fibers  (preganglionic)  of  the  pars  in- 
termedia of  the  facial  nerve  (n.  intermedius,  n.  glossopalatinus) .  These 
fibers  arise  in  the  medulla  oblongata  from  a  group  of  cells  in  the  reticular 


SPHENOPALATINE  GANGLION  AND  ITS  CONNECTIONS  315 

formation  dorsal  and  medial  to  the  facial  nucleus,  pass  through  the  genicu- 
late  ganglion  and  become  component  fibers  of  the  great  superficial  petrosal 
nerve  (n.  petrosus  superficial  major)  and  the  nerve  of  the  pterygoid 
canal  (n.  canalis  pterygoidei  Vidii,  Vidian  nerve)  and  reach  their  termi- 
nation in  the  sphenopalatine  ganglion  by  arborizing  or  synapsing  there 
with  the  cell  bodies  of  postganglionic  neurons  (see  neurons  numbered  6 
in  the  diagram,  Fig.  201).  A  few  of  the  visceral  motor  fibers  (pregan- 
glionic)  arising  within  the  medulla  oblongata  terminate  within  the  genicu- 
late  ganglion  by  synapsing  with  the  cell  bodies  of  postganglionic  neurons. 


FIG.  201. — Schema  showing  the  connections  of  the  sphenopalatine  (Meckel's,  nasal)  ganglion. 

A  =  Sensory  root;  B  =  Motor  root;  C  =  Sympathetic  root.  See  text,  pages  314  to  317,  for  a 
consideration  of  the  component  fibers  of  the  so-called  roots  of  the  ganglion.  The  reference  numbers 
are  explained  in  the  text. 

The  peripheral  processes  of  some  of  the  latter  neurons  follow  the  great 
superficial  petrosal  nerve  and  the  nerve  of  the  pterygoid  canal  of  Vidian, 
pass  through  the  sphenopalatine  ganglion  without  interruption  to  be  dis- 
tributed via  the  ganglionic  branches  (see  neuron  numbered  7  in  the 
diagram,  Fig.  201). 

It  is  also  established  that  a  number  of  somatic  sensory  neurons  with 
cell  bodies  located  in  the  geniculate  ganglion  are  associated  with  or  rather 


3i6  THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 

are  a  part  of  the  so-called  motor  root  of  the  sphenopalatine  ganglion. 
The  peripheral  processes  of  these  somatic  sensory  neurons  follow  the  great 
superficial  petrosal  and  the  Vidian  nerves,  pass  through  the  spheno- 
palatine ganglion  uninterrupted  and  descend  in  the  small  palatine  nerve 
to  the  soft  palate  and  adjacent  parts  of  the  pharynx  where  some  are 
seemingly  concerned  with  the  gustatory  function  and  others  with  general 
sensation.  The  central  processes  of  these  somatic  sensory  neurons  termi- 
nate about  cells  at  the  upper  pole  of  the  nucleus  of  the  alar  cinerea  in  the 
medulla  (see  neuron  numbered  13  in  the  diagram,  Fig.  201).  Moreover, 
there  is  supporting  evidence  that  there  are  sympathetic  afferent  neurons 
associated  with  the  motor  root  of  the  sphenopalatine  ganglion.  The 
cell  bodies  of  these  neurons  are  located  in  the  geniculate  ganglion,  the 
peripheral  processes  of  which  follow  the  same  course  as  the  somatic  sensory 
neurons,  above  referred  to,  save  that  the  sympathetic  afferents  enjoy 
a  wider  distribution,  including  among  other  parts  the  nasal  cavity.  The 
central  connections  of  the  sympathetic  afferents  are  not  definitely  es- 
tablished (see  neurons  numbered  9  in  the  diagram,  Fig.  201). 

The  great  superficial  petrosal  nerve  is  usually  spoken  of  as  the  motor 
root  of  the  sphenopalatine  ganglion.  It  is,  however,  obvious  from  the 
foregoing  that  the  nerve  is  not  merely  motor  in  its  composition,  but  that  in 
addition  to  the  motor  and  most  numerous  fibers,  it  contains  sensory 
(somatic  and  sympathetic)  fibers.  The  great  superficial  petrosal  arises 
from  the  geniculate  ganglion  of  the  pars  intermedia  of  the  facial  nerve 
in  the  facial  canal  (canalis  f acialis) ,  passes  through  the  hiatus  of  the  facial 
canal  (hiatus  canalis  f  acialis,  hiatus  Fallopii)  and  a  groove  in  the  petrous 
portion  of  the  temporal  bone  in  the  middle  cerebral  fossa.  It  now  courses 
under  the  semilunar  (Gasserian)  ganglion  to  the  position  of  the  middle 
lacerated  foramen  (foramen  lacerum)  where  it  is  joined  by  the  great  deep 
petrosal  (n.  petrosus  profundus  major)  or  the  so-called  sympathetic  root 
of  the  sphenopalatine  ganglion.  The  great  superficial  and  the  great  deep 
petrosal  nerves  merge  over  the  cepahlic  surface  of  the  cartilage  of  the 
middle  lacerated  foramen  in  the  formation  of  the  nerve  of  the  ptery gold- 
canal  of  Vidian.  The  latter  with  accompanying  blood-vessels  traverses 
the  pterygoid  canal  in  the  root  of  the  pterygoid  process  of  the  sphenoid 
bone,  enters  the  sphenopalatine  (sphenomaxillary)  fossa,  there  to  connect 
with  the  sphenopalatine  ganglion  located  on  the  lateral  side  of  the  spheno- 
palatine foramen  (Fig.  145). 

The  sympathetic  root  of  the  sphenopalatine  ganglion  is  the  great  deep 
petrosal  nerve  (n.  petrosus  profundus  major)  which  is,  in  a  sense,  a  direct 
extension  of  the  carotid  plexus.  Indeed,  the  great  deep  petrosal  nerve 


SPHEXOPALATINE  GANGLION  AND  ITS  CONNECTIONS  317 

may  be  considered  the  connecting  or  association  fasciculus  between  the 
superior  cervical  sympathetic  ganglion  and  the  sphenopalatine  sympathetic 
ganglion.  Most  of  its  fibers  are  the  peripheral  processes  (axons)  of 
postganglionic  neurons  arising  from  cell  bodies  located  in  the  superior 
cervical  sympathetic  ganglion.  These  postganglionic  fibers  pass  through 
the  sphenopalatine  ganglion  uninterrupted  for  distribution  by  way  of  the 
ganglionic  branches  (see  neurons  numbered  2  in  the  diagram,  Fig.  201). 
Moreover,  a  few  of  the  fibers  contained  in  the  great  deep  petrosal  nerve  are 
seemingly  the  peripheral  processes  of  preganglionic  neurons  arising  from 
cell  bodies  located  in  the  ventral  horns  of  the  upper  thoracic  spinal  cord 
segments.  These  preganglionic  fibers  end  in  arborizations  or  synapses 
around  the  stellate  cell  bodies  of  postganglionic  neurons  located  in  the 
sphenopalatine  ganglion  (see  neurons  numbered  i  in  the  diagram,  Fig.  201). 
In  addition  to  the  motor  elements  the  great  deep  petrosal  nerve  apparently 
contains  sympathetic  afferent  fibers,  the  cell  bodies  of  which  are  located 
in  the  ganglia  of  the  dorsal  roots  of  the  upper  thoracic  spinal  nerves. 
Further  study  is  necessary  to  definitely  establish  these  afferent  sym- 
pathetic elements.  Certain  laboratory  experiences  and  clinical  evidence 
tend  to  support  the  existence  of  sympathetic  afferent  elements  in  the  great 
deep  petrosal  nerve  (see  neurons  numbered  8  in  the  diagram). 

The  sensory  root  of  the  sphenopalatine  ganglion  consists  of  the  spheno- 
palatine nerve  or  nerves,  e.g.,  of  two  to  three  short,  stout  trunks  connecting 
the  maxillary  nerve  with  the  upper  border  of  the  ganglion  (see  page  307). 
Most  of  the  component  fibers  of  the  sensory  root  are  peripheral  processes 
or  dendrites  of  cell  bodies  located  within  the  semilunar  (Gasserian) 
ganglion  of  the  trigeminal  nerve.  A  few  of  these  sensory  fibers  end  in  the 
sphenopalatine  ganglion  for  the  supply  of  the  capsule  of  the  ganglion  and 
the  capsules  of  its  contained  cell  bodies  (see  neuron  numbered  3  in  the 
diagram,  Fig.  201).  However,  the  vast  majority  of  the  fibers  of  the 
sensory  root  pass  either  around  or  through  the  sphenopalatine  ganglion 
without  interruption  in  synapses  to  be  distributed  by  way  of  the  numerous 
ganglionic  branches  (see  neurons  numbered  4  in  the  diagram,  Fig.  201). 

There  is  some  evidence  that  a  few  axons  of  postganglionic  neurons 
(motor  sympathetic)  with  cell  bodies  located  within  the  sphenopalatine 
ganglion  pass  by  way  of  the  sensory  root  to  be  distributed  with  the 
somatic  sensory  fibers  of  the  maxillary  nerve  (see  neuron  numbered  10  in 
diagram) . 

The  branches  of  the  sphenopalatine  ganglion  are  (i)  orbital  (ascend- 
ing), (2)  palatine  (descending),  (3)  pharyngeal  (dorsal),  and  (4)  nasal 
(medial).  In  accordance  with  the  foregoing  paragraphs  they  contain 


3i8  THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 

vasomotor,  secretory1  and  sensory  fibers.  The  reader  is  referred  to  pages 
306  to  310  for  a  discussion  of  the  ganglionic  branches  in  their  distribu- 
tion to  the  nasal  fossa,  the  paranasal  chambers,  etc. 

The  Anatomic  Relations  of  the  Sphenopalatine  Ganglion. — The 
small  flattened  triangular  body  of  the  sphenopalatine  or  nasal  ganglion 
measures  from  5  to  8  mm.  in  its  sagittal  plane  and  has  its  apex 
directed  dorsally.  It  occupies  a  relatively  deep  position  in  the  pterygo- 
palatine  or  sphenomaxillary  fossa,  just  caudal  to  the  maxillary  nerve 
and  in  advance  of  the  ventral  extremity  of  the  pterygoid  (Vidian)  canal 
and  in  close  proximity  to  the  lateral  side  of  the  sphenopalatine  foramen. 

In  order  that  one  may  more  fully  appreciate  the  position  and  relations 
of  the  sphenopalatine  ganglion,  it  is  deemed  advisable  that  the  pterygo- 
palatine  (sphenomaxillary)  fossa  be  briefly  considered.  This  fossa  rep- 
resents in  form  a  small  inverted  pyramid  located  at  the  point  of  juncture 
of  the  inferior  orbital  (sphenomaxillary)  with  the  pterygopalatine  (pterygo- 
maxillary)  fissures  somewhat  caudal  to  the  apex  of  the  orbit.  The  fossa 
is  bounded  ventratty  by  the  infratemporal  surface  of  the  maxilla;  dorsally 
by  the  base  of  the  pterygoid  process  and  the  ventral  surface  of  the  great 
wing  of  the  sphenoid;  medially  by  the  perpendicular  plate  of  the  palate 
bone  with  its  orbital  and  sphenoidal  processes;  and  cephalically  by  the 
caudal  surface  of  the  body  of  the  sphenoid  bone.  Three  important  fis- 
sures terminate  in  the  pterygopalatine  fossa;  e.g.,  the  superior  orbital, 
the  pterygopalatine  and  the  inferior  orbital ;  leading  thereby  to  a  connec- 
tion with  the  cranial  cavity,  the  infratemporal  fossa  and  the  orbital 
cavity,  respectively.  In  the  articulation  of  the  palate  bone  with  the 
sphenoid,  the  sphenopalatine  notch  of  the  former,  forms  with  the  sphenoid 
bone  a  window  or  aperture,  the  sphenopalatine  foramen,  communicating 
between  the  pterygopalatine  and  the  nasal  fossae  immediately  dorsal 
to  the  superior  nasal  meatus  and  caudal  to  the  body  of  the  sphenoid. 
Six  foramina  communicate  with  the  pterygopalatine  fossa:  one,  the 
sphenopalatine,  on  the  medial  wall;  three,  the  foramen  rotundum,  the 
pterygoid  (Vidian)  canal  and  the  pharyngeal  (pterygopalatine)  canal,  on 
the  dorsal  wall;  one,  the  orifice  of  the  infraorbital  canal,  on  the  ventral 
wall;  and  caudally  the  apex  of  the  pterygopalatine  fossa  narrows  into 
and  continues  as  the  pterygopalatine  (posterior  palatine)  canal  and  the 
accessory  palatine  canals. 

.When  one  recalls  the  structures  that  either  enter  or  are  wholly 

1  Prevost  found  that  feeble  electrical  stimulation  of  the  exposed  sphenopalatine  ganglion  caused 
a  copious  secretion  of  mucus  in  the  nasal  fossa.  Moreover,  an  increase  in  the  nasal  temperature  and 
dilatation  of  the  blood-vessels  was  noted. 


TOPOGRAPHY  OF  SPHEXOPALATIXE  GANGLION  319 

located  within  the  pterygopalatine  fossa,  such  as  the  maxillary  nerve, 
the  Vidian  nerve,  the  sphenopalatine  ganglion  with  its  outflowing  branches, 
etc.;  moreover,  that  the  sphenoidal  and  posterior  ethmoidal  air  cells 
very  commonly  encroach  to  a  marked  degree  upon  the  confines  of  the 
pterygopalatine  fossa  and  secondarily  upon  the  contained  structures, 
one  at  once  appreciates  the  importance  of  a  clear  understanding  of  the 
anatomic  relationships,  e.g.,  the  topographic  anatomy,  of  the  region  of  the 
pterygopalatine  fossa  in  dealing  with  nasal  and  paranasal  disorders. 

Owing  to  the  position  of  the  sphenopalatine  ganglion  in  the  spheno- 
palatine fossa  in  close  proximity  to  the  sphenopalatine  foramen,  it  is 
subject  to  surface  influences  from  both  the  nasal  fossa  and  certain  para- 
nasal  (accessory)  sinuses.  The  nasal  mucous  membrane  and  a  variable 
but  small  amount  of  areolar  tissue  alone  intervene  between  the  ganglion 
and  the  nasal  cavity  in  the  recent  or  undissected  state.  The  intimacy 
of  the  relationship  between  the  ganglion  and  the  nasal  mucosa  varies  to  a 
limited  degree  in  different  individuals.  Moreover,  the  size  of  the  spheno- 
palatine foramen  is  variable  and  when  unduly  large  increased  mucosal 
relations  necessarily  obtain.  The  extreme  pneumatizations  of  the 
sphenoidal  and  posterior  ethmoidal  cells  commonly  encountered  lead  to 
additional  intimate  and  important  relations  between  the  respiratory 
mucous  membrane  and  the  sphenopalatine  ganglion.  A  lamina  of  bone 
of  papery  delicacy  and  mucous  membrane  not  infrequently  alone  intervene 
between  the  outside  air  and  the  ganglion.  Indeed,  the  bone  may  be 
actually  wanting,  e.g.,  dehiscences  may  be  present,  thereby  bringing  the 
ganglion  into  intimate  relationship  or  actual  contact  with  the  mucous 
membrane  of  the  paranasal  sinuses  in  question.  It  is  particularly  in 
those  cases  in  which  the  sphenoidal  sinus  extends  ventrocaudally  recess- 
like  into  the  pterygoid  process  (base  and  laminae)  of  the  sphenoid  and 
into  the  orbital  process  of  the  palate  bone  and  occasionally  into  the 
ethmoid  bone  by  encroachment  on  posterior  ethmoidal  cells  or  by  replac- 
ing them  that  the  very  intimate  ganglionic  relationships  are  established. 
The  intimacy  of  the  relationship  is,  of  course,  dependent  upon  the  direc- 
tion and  degree  of  the  pneumatization  (Figs.  145  and  139).  At  times  a  pos- 
terior ethmoidal  cell  (or  cells)  replaces  the  extension  of  the  sphenoidal  sinus 
into  the  orbital  process  of  the  palate  bone.  Indeed,  ethmoidal  extensions 
may  take  place  into  the  sphenoid  bone,  even  pneumatizing  into  the  root 
of  the  pterygoid  process.  In  such  cases  the  sphenopalatine  ganglion 
bears  a  much  more  intimate  relationship  to  the  posterior  ethmoidal  cell  or 
cells  than  it  does  to  the  sphenoidal  sinus. 

Witness,  for  example,  the  dissection  represented  in  Fig.  135.     Here 


320  THE  COMMON  SENSORY  AND  THE  SYMPATHETIC  NERVES 

the  sphenoidal  sinus  on  the  right  side  of  the  body  shows  extensive  pneu- 
matization  extending  to  the  left  beyond  the  mid-sagittal  plane  at  the 
expense  of  its  fellow.  The  right  sinus  has  pneumatized  into  the  basilar 
process  of  the  occipital  bone,  the  pterygoid  process  of  the  sphenoid  bone, 
the  orbital  process  of  the  palate  bone,  and  has  actually  extended  forward 
into  the  dorsal  extremity  of  the  ethmoid  bone.  The  sphenoidal  extension 
into  the  orbital  process  of  the  palate  bone  (the  palatine  recess  of  the 
sphenoidal  sinus)  is  separated  from  the  dorsocephalic  extension  of  the 
maxillary  sinus  by  a  mere  film  of  bone.  A  large  posterior  ethmoidal 
cell  has  likewise  pneumatized  into  the  orbital  process  of  the  palate  bone 
and  is  throughout  separated  from  the  sphenoidal  sinus  by  an  extremely 
thin  lamella  of  bone.  It  is  obvious  in  such  specimens  that  involvement 
of  the  sphenoidal  sinus  or  of  the  posterior  ethmoidal  cell  may  readily  in- 
fluence the  maxillary  sinus  and  vice  versa.  Moreover,  these  several 
sinuses,  due  to  the  extreme  pneumatization,  establish  the  most  intimate 
relationship  with  the  sphenopalatine  foramen  and  the  sphenopalatine 
ganglion.  Sometimes  posterior  ethmoidal  cells  are  superimposed,  one 
over  the  other;  the  more  caudally  placed  of  which  is  the  more  intimately 
related  to  the  sphenopalatine  ganglion.  Again,  a  posterior  ethmoidal  cell 
may  extend  its  pneumatization  into  the  body  of  the  sphenoid  bone  and 
replace  the  ventrosuperior  portion  of  the  sphenoidal  sinus.  This  does, 
however,  not  preclude  the  extension  of  the  sphenoidal  sinus  into  the  root 
of  the  pterygoid  process  and  its  encroachment  upon  the  pterygopalatine 
fossa  with  its  contained  sphenopalatine  ganglion  (Fig.  155). 

Anatomical  Relations  of  the  Nerve  of  the  Pterygoid  Canal. — In  a 
study  dating  from  1907*  the  author  has  had  opportunity  to  observe  the 
relations  of  the  nerve  of  the  pterygoid  canal  (Vidian  nerve)  in  an  extreme!}' 
large  number  of  cadavers.  These  observations  were  made  in  regular 
dissections  and  in  sections  through  the  various  planes  and  at  different 
ages.  In  many  of  the  specimens  studied  the  floor  of  the  sphenoidal  sinus 
is  separated  from  the  pterygoid  (Vidian  canal)  by  a  fairly  thick  layer 
of  compact  bone.  However,  there  are  a  large  percentage  of  specimens 
in  which  the  sphenoidal  sinus  extends  its  pneumatization  caudally  and 
ventrally  into  the  root  of  the  pterygoid  process  (Fig.  139).  Indeed,  the 
extension  may  pass  beyond  this,  either  medially  or  laterally  or  both, 
into  the  plates  of  the  pterygoid  process.  In  such  instances  the  pterygoid 
canal  with  its  contained  Vidian  nerve  and  vessels  is  at  best  merely  sepa- 
rated from  the  mucous  membrane  of  the  sphenoidal  sinus  by  an  extremely 

1  The  first  reference  by  the  author  concerning  these  observations  was  made  at  an  Anatomical 
Seminar  at  Cornell  University  in  1909. 


TOPOGRAPHY  OF  V1DIAX  NERVE  321 

delicate  layer  of  bone.  Indeed,  in  the  majority  of  such  cases  the  canal 
is  thrown  into  marked  relief  in  the  floor  of  the  sphenoidal  sinus  so  that  it  forms 
a  distinct  watershed  dividing  a  lateral  from  a  medial  pterygoid  diverticulum 
or  recess  of  the  sphenoidal  sinus.  Again,  it  is  not  an  unusual  condition 
to  find  pterygoid  canals  in  which  the  thin  layer  of  bone  is  actually  want- 
ing (dehiscences),  thereby  exposing  the  contained  Vidian  nerve  and 
accompanying  blood-vessels  to  the  influences  of  the  outside  atmosphere 
or  of  an  infected  sphenoidal  sinus.  The  mucous  membrane  of  the 
sphenoidal  sinus  alone  is  interposed  between  the  sinus  cavity  and  the 
Vidian  nerve,  etc.  Witness,  for  example,  Figs.  133,  139,  195  and  197  in 
which  the  nerve  of  the  pterygoid  canal  courses  across  the  cavity  of  the 
sphenoidal  sinus  at  a  considerable  distance  above  the  sinus  floor  proper, 
thereby  throwing  the  mucous  membrane  into  marked  relief.1 

1  See  also  Greenfield  Sluder,  Archiv.  f.  Laryngol.  u.  Rhin.,  Bd.  27,  Heft.  3,  1913;  Annals  Otol., 
Rhin.  and  Laryngol.,  1913,  1914,  and  Ladislaus  Onodi,  Jour.  Laryng.,  Rhin.  and  Otol.,  1914,  for  in- 
structive and  valuable  anatomico-clinical  considerations  of  the  Vidian  and  other  nerves. 


XI-THE  OLFACTORY  APPARATUS  PROPER 


CHAPTER  XI 
THE  OLFACTORY  APPARATUS  PROPER 

The  olfactory  apparatus  proper  may,  for  convenience  of  description, 
be  divided  into  a  central  organ  and  a  peripheral  organ,  the  former  extra- 
nasal  in  position  and  the  latter  intranasal.  The  peripheral  organ  especially 
concerns  us  in  this  work  and  some  phases  of  its  anatomy  were  previously 
considered  in  connection  with  the  nasal  mucous  membrane.  The  central 
organ  will  be  but  briefly  alluded  to,  and  it  will  suffice  in  subsequent  para- 
graphs to  point  out  the  general  features  of  the  olfactory  brain  and  to  refer 
to  the  more  important  pathways  involved  in  olfactory  reflexes  and  those 
which  serve  in  carrying  afferent  olfactory  impulses  to  the  cerebral  cortex 
and  efferent  voluntary  impulses  of  cortical  origin  in  which  the  olfactory 
element  predominates. 

A.  THE  PERIPHERAL  ORGAN 

The  peripheral  organ  of  smell  in  adult  man  is  the  specific  sensory 
epithelium  wdthin  the  nasal  fossae — the  extent  of  which  was  discussed 
previously  under  the  caption  " nasal  mucous  membrane."  The  perceptive 
elements  (the  olfactory  receptors,  the  olfactory  cells)  of  the  nasal  mucosa 
are  bipolar,  with  short  peripheral  and  long  central  processes — the  latter 
the  olfactory  nerves.  The  peripheral  olfactory  tract  extends  from  the 
olfactory  portion  of  the  nasal  mucous  membrane  to  the  intracranial  ol- 
factory bulb,  and  its  elements  are  neurons  of  the  first  order.  The  impulse 
is  conducted  by  the  peripheral  processes  (dendrites)  to  the  bipolar  cell 
bodies,  thence  by  the  central  processes  (axons)  to  the  olfactory  bulb. 

In  some  of  the  lower  vertebrates,  and  in  mammals  with  a  highly  de- 
veloped sense  of  smell,  three  nerves  are  apparently  concerned  with  the 
peripheral  olfactory  organ:  (i)  the  olfactory  nerve  proper,  (2)  the  termi- 
nal nerve,  and  (3)  the  vomeronasal  nerve.  In  man  the  latter  is  absent 
owing  to  the  rudimentary  state  of  the  vomeronasal  organ  of  Jacobson. 
Moreover,  the  terminal  may  not  be  a  special  sense  nerve,  but  prove  to 
consist  of  postganglionic  neurons,  with  cell  bodies  located  in  the  terminal 
ganglion  for  the  supply  of  unstriped  muscle  and  glands  (motor  and  secre- 
tory), thus  conforming  to  the  postganglionic  fibers  distributed  to  the  nasal 

325 


326  THE  OLFACTORY  APPARATUS  PROPER 

cavity,  e.g.,  the  fibers  from  the  sphenopalatine  ganglion  (Meckel's),  etc. 
(see  page  306). 

The  Olfactory  Nerve  (Nervus  olfactorius). — In  man  approximately 
twenty  non-medullated  olfactory  nerve  filaments  (the  axons  or  central 
processes  of  the  bipolar  olfactory  cells)  issue  from  the  olfactory  mucosa 
near  the  lamina  cribrosa  of  the  ethmoid  bone.  These  filaments  (the  ol- 
factory nerves,  collectively  the  olfactory  nerve)  pass  at  once  through  the 
foramina  of  the  cribriform  lamina  in  two  rows,  medial  and  lateral.  After 
entering  the  anterior  cerebral  fossa  the  olfactory  filaments  pierce  the 
cerebral  meninges  and  enter  the  olfactoiy  bulb,  there  to  synapse  with  the 
dendrites  of  the  mitral  cells  in  formations  known  as  the  olfactory  glomeruli. 
The  latter  contain  the  first  synapse  in  the  olfactory  pathway  (Fig.  202). 

Since  the  days  of  Scarpa  anatomists  considered  the  olfactory  nerves 
as  forming  a  plexus  in  their  passage  from  the  olfactory  cells  to  the  olfac- 
tory bulb.  Figures  from  the  writings  of  Scarpa  and  Leveille,  the  latter 
doubtless  influenced  by  the  former,  were  frequently  copied  into  text-books. 
Even  to-day  new  books  appear  with  adaptations  from  the  illustrations  of 
the  above  authors.  However,  the  researches  of  Miss  Read1  show  that, 
instead  of  a  plexiform  arrangement,  the  olfactory  nerves  "extend  in  non- 
anastomosing  bundles  to  the  olfactory  bulb ;  all  appearance  of  anastomo- 
sis being  due  (a)  to  a  crossing  of  the  bundle  of  nerves  or  (b)  to  a  net-like 
arrangement  of  the  connective  tissue  or  blood-vessels." 

The  Terminal  Nerve  (Nervus  terminalis). — The  terminal  nerve  is 
a  slender  and  variably  plexiform  nerve.  It  contains  both  medullated 
and  non-medullated  fibers  (the  latter  predominate),  and  unlike  the  ol- 
factory and  vomeronasal  nerves  is  ganglionated. 

The  terminal  nerve  is  found  in  many  classes  of  vertebrates  from  fishes 
to  man.  In  man  it  has  been  satisfactorily  demonstrated  in  fetuses  and 
infants.  The  author  has  dissected  the  nerve  in  a  number  of  infants.  Her- 
rick  states  that  the  nerve  is  present  also  in  the  adult.  Its  peripheral  twigs 
are  found  distributed  to  the  mucous  membrane  of  the  nasal  septum  and 
to  the  mucosa  joining  the  olfactory  region  proper.  Furthermore,  it  has 
been  shown  that  the  terminal  nerve  accompanies  and  shares  the  distri- 
bution of  the  vomeronasal  nerve  when  the  latter  is  present.  The  exact 
ending  of  the  peripheral  twigs  of  the  terminal  nerve  is  unknown.  Cen- 
trally the  nerve  passes  through  the  cribriform  plate  of  the  ethmoid  bone 
in  company  with  the  olfactory  nerve  (or  nerves)  in  the  form  of  two  or  three 
small  roots  mesial  to  the  vomeronasal  nerve.  The  roots  of  the  terminal 
nerve  pass  over  the  inferior  mesial  aspect  of  the  olfactory  bulb,  here  leave 

1  The  American  Journal  of  Anatomy,  Vol.  8,  1908. 


TERMINAL  NERVE  327 

the  olfactory  fibers,  continue  dorsally  to  enter  the  brain  in  the  region  of 
the  olfactory  trigone. 

The  function  of  the  terminal  nerve  is  obscure.  It  may  contain  both 
afferent  and  efferent  fibers  (Johnson).  It  is  well  known  that  groups 
of  ganglion  cells  are  found  along  the  extra-  and  intracranial  courses  of  the 
nerve.  Some  describe  the  ganglion  cells  and  the  fibers  as  having  the 
characteristics  of  the  sympathetic  neurons.  Hardesty  suggests  that,  in- 
stead of  being  an  independent  nerve  as  now  claimed,  the  nervus  terminalis 
may  be  a  part  of  the  forward  extension  of  the  cephalic  sympathetic  and 
that  its  neurons  receive  and  convey  impulses  to  the  gland  cells  of  the  nasal 
mucosa  and  to  the  unstriped  muscles  of  the  blood-vessels  of  the  nasal 
mucosa  and  those  supplying  the  inf eromesial  part  of  the  frontal  end  of  the 
cerebrum.  Others  believe  that  the  fibers  of  the  terminal  nerve  may  be 
followed  through  the  length  of  the  olfactory  area  and  hypothalamus,  ad- 
mitting ignorance,  however,  of  the  exact  cerebral  connection.  Herrick 
states:1  "The  problem  of  the  functional  and  morphological  relationships 
of  the  nervus  terminalis  must  be  solved  before  a  complete  understanding 
of  the  olfactory  nerve  itself  is  possible.  It  may  be  that  the  nervus  termi- 
nalis is  a  remnant  of  a  nerve  of  general  chemical  sensibility  of  the  nose 
region  which  has  been  largely  supplanted  by  the  more  highly  developed 
chemical  receptors  of  the  specific  olfactory  system.  On  the  other  hand,  it 
may  be  a  nerve  of  general  visceral  efferent  type,  the  cells  of  the  ganglion 
terminale  being  postganglionic  sympathetic  neurons." 

Brookover, 2  in  a  discussion  of  "the  peripheral  distribution  of  the 
nervus  terminalis  in  an  infant,"  summarizes  briefly  by  saying  that  the 
peripheral  nervus  terminalis  is  so  large  in  man  that  it  may  be  said  to  be 
hypertrophied  as  compared  to  the  known  development  in  other  mammals, 
without  especially  increasing  its  central  root.  In  addition  to  many  cells 
in  the  ganglion  terminale,  it  contains  about  fifteen  hundred  cells  periph- 
erally under  the  nasal  mucosa.  Though  disposed  in  three  or  four  chief 
rami  emerging  from  the  lamina  cribrosa,  there  is  a  vast  network  of  inter- 
lacing bundles  deep  to  the  main  arteries.  Some  of  the  fibers  trail  over  the 
walls  of  the  arteries,  but  the  method  of  treatment  by  the  silver  technic 
does  not  reveal  ultimate  endings. 

The  Vomeronasal  Nerve  (Nervus  vomeronasalis). — The  vomeronasal 
nerve  is  composed  of  central  processes  of  nerve  cells  located  in  the  mucosa 
of  the  vomeronasal  organ  (of  Jacobson).  Since  the  latter  is  rudimentary 
and  probably  functionless  as  an  olfactory  organ  in  adult  man,  the  vomero- 

1  Introduction  to  Neurology,  Philadelphia,  1916. 

2  The  Journal  of  Comparative  Neurology,  Vol.  28,  1917. 


328  THE  OLFACTORY  APPARATUS  PROPER 

nasal  nerve  is  absent.  In  those  forms  in  which  the  vomeronasal  organ 
functions  in  olf action,  e.g.,  in  the  dog,  cat,  rabbit,  etc.,  the  vomeronasal 
nerve  passes  into  the  submucosa  and  joins  the  filaments  of  the  olfactory 
nerve  proper.  The  nerve  fibers  terminate  in  the  accessory  olfactory 
bulb  on  the  posteromedian  aspect  of  the  olfactory  bulb  proper.  In  am- 
phibia the  vomeronasal  organ  is  supplied  by  fibers  from  the  vomeronasal, 
terminal  and  olfactory  nerves.  Read1  has  also  shown  that  in  man  a  branch 
of  the  olfactory  nerve  passes  to  the  vomeronasal  organ,  at  least  at  the  time 
of  birth.  Some  would  consider  the  vomeronasal  nerve  as  a  special  slip 
of  the  olfactory  nerve  and  as  terminating  in  a  specially  differentiated 
portion  of  the  olfactory  bulb — the  formatio  vomeronasalis  of  McCotter. 
In  adult  man  the  vomeronasal  region  seems  to  be  for  general  sensation 
only  and  is,  therefore,  supplied  by  the  trigeminus  nerve  and  by  the  cephalic 
sympathetic  fibers  common  to  the  mucosa  of  the  general  nasal  fossa. 

B.  THE  CENTRAL  ORGAN 

The  olfactory  region  of  the  telencephalon  or  end  brain  is  usually 
referred  to  as  the  rhinencephalon,  a  term  of  doubtful  utility  owring  to  its 
varied  application  by  anatomists.  It  is  a  well  established  fact  that  the 
olfactory  brain  is  phylogenetically  the  oldest  part  of  the  cerebral  hemisphere 
and  that  it  is  early  differentiated  ontogenetically.  Owing  to  the  fact  that 
it  is  the  oldest  part  of  the  cerebral  hemisphere  in  vertebrate  evolution, 
it  is  often  termed  the  archipallium  as  distinguished  from  the  greater  por- 
tion of  the  remainder  of  the  hemisphere — the  neopallium  (the  corpus 
striatum  is  not  a  portion  of  the  latter). 

The  rhinencephalon  is  reduced  to  a  comparatively  rudimentary 
state  in  man  and  primates  generally,  being  greatly  overshadowed  by  the 
non-olfactory  portion  of  the  cerebral  hemisphere.  This  reduction  is, 
doubtless,  due  to  the  relatively  feeble  olfactory  sense  in  these  forms.  The 
archipallium  reaches  its  highest  development  in  the  lowest  mammals 
and  the  neopallium  attains  its  maximum  size  in  man. 

The  Olfactory  Brain. — The  portions  of  the  human  brain  connected 
with  the  olfactory  apparatus  may  be  said  to  include  the  very  rudimentary 
olfactory  lobe,  the  hippocampus  and  the  uncus  and  certain  accessory 
parts.  These  structures  are  either  wholly  or  partly  associated  with  the 
function  of  smell.  From  the  viewpoint  of  morphology  the  olfactory 
brain  or  rhinencephalon  may  be  divided  into  an  anterior  and  a  posterior 
division.  The  former  consists  of  the  several  portions  of  the  olfactory 
lobe  and  the  latter  of  certain  other  parts  (Fig  203) : 

1  The  American  Journal  of  Anatomy,  Vol.  8,  1908. 


329 


Olfactory  Lobe 


Olfactory  Cortex 
and  Accessory 
Parts 


OLFACTORY  BRAIN 

(a)  Olfactory  bulb 

(b)  Olfactory  tract 

(c)  Olfactory  trigone     ' 

(d)  Anterior  perforated  substance 

(e)  Parolfactory  area  (of  Broca) 

( (/)  Subcallosal  gyrus  (peduncle  of  corpus  callosum) 

(a)  Uncus  (gyrus  uncinatus) 

(6)  Hippocampus  (hippocampus  major) 

(c)  Amygdaloid  nucleus 

(d)  Supracallosal    gyrus,    including    the  medial  and 

lateral  striae  (gyrus  epicallosus,  indusium  griseum) 

(e)  Dentate  fascia  (gyrus  dentatus) 

(/)  Septum  lucidum  (septum  pellucidum) 

(g)  Fornix 

(h)  Fimbria 

(/)  Mammillary  body 

(j)  Habenular  nucleus 

(k)  Thalamus  (optic  thalamus) 

(/)  Anterior  cerebral  commissure 

(m)  Medullary  stria  of  thalamus 

(n)  Mammillo-thalamic  fasciculus 

(0)  Mammillo-peduncular  fasciculus 

(p)  Terminal  stria  of  thalamus  (taenia  semicircularis) 

(q)  Habenulo-peduncular  fasciculus 

(r)  Etc. 

The  hippocampus  (the  curved  eminence  which  extends  throughout  the 
floor  of  the  inferior  cornu  of  the  lateral  ventricle)  and  the  uncus,  while 
chiefly  functioning  as  the  olfactory  cortex,  give  off  many  association  path- 
ways for  connection  with  other  parts  of  the  cerebral  cortex.  The  hip- 
pocampal  gyrus  and  the  callosal  (cingulate)  gyrus,  collectively  the  gyrus 
fornicatus  or  the  limbic  lobe  of  Broca,  are  not  here  considered  parts  of  the 
rhinencephalon.  Broca,  on  the  contrary,  associated  the  limbic  lobe  with 
the  center  for  olfaction.  However,  a  comparatively  small  part  of  his 
limbic  lobe  appears  to  be  specially  olfactory  in  function.  Although  in 
superficial  continuity  with  the  hippocampal  gyrus,  Turner  and  Elliot 
Smith  have  shown  that  the  uncus  forms  morphologically  a  part  of  the 
rhinencephalon  and  not  of  the  limbic  lobe  as  frequently  stated.  Histo- 
logical  evidence  also  tends  to  indicate  that  the  chief  cortical  termination 
of  the  olfactory  paths  is  located  in  the  uncus  and  the  hippocampus.  More- 
over, Ferrier  finds  that  electrical  stimulation  in  this  region  is  followed  by 
tortion  of  the  lips  and  nostrils  of  the  same  side;  muscular  movements  that 
accompany  strong  olfactory  excitations.  Ablations  of  the  uncal  region 
are  followed  by  defects  in  the  sense  of  smell. 

The  accessory  parts  of  the  rhinencephalon  particularly  serve  in  a 
collective  sense  as  pathways  by  which  olfactory  cortical  centers  are  con- 
nected with  each  other,  on  the  one  hand,  and  with  the  thalamus  (optic 


330  THE  OLFACTORY  APPARATUS  PROPER 

thalamus),  etc.,  on  the  other.  Furthermore,  these  pathways  serve  to 
connect  the  cortical  centers  with  lower  levels  of  the  brain.  The  olfactory 
cerebral  centers  fall  into  two  groups,  e.g.,  the  olfactory  cerebral  cortex 
and  the  reflex  centers  of  the  brain  stem.  Olfactory  impulses  destined 
for  the  cerebral  cortex  follow  different  pathways  from  those  involved  in 
olfactory  reflexes. 

The  olfactory  bulb  (bulbus  olfactorius)  and  tract  (tractus  olfactorius) 
are  located  on  the  inferior  or  orbital  surface  of  the  brain  and  constitute 
a  goodly  portion  of  the  cerebral  hemisphere  with  extension  of  the  ventricu- 
lar cavity  in  many  vertebrates;  for  example,  the  horse.  In  man,  on  the 
contrary,  the  ventricular  (lateral  ventricle)  prolongation,  while  present 
at  first,  gradually  becomes  obliterated  and  filled  in  by  the  central  neuroglia 
of  the  olfactory  bulb  and  tract  and  the  whole  olfactory  lobe  reduced  to 
a  rudimentary  state.  The  neuroglia  core  is  demonstrable  in  sections  of 
the  adult  bulb  and  tract  as  a  gelatinous  substance. 

The  olfactory  bulb  is  an  elongated,  oval  body  of  gray  matter  resting 
upon  the  lamina  cribrosa  of  the  ethmoid  bone.  It  is  essentially  free  save 
that  the  filaments  of  non-medullated  axons  of  the  olfactory  nerve  enter 
its  ventral  surface.  Its  confines  are  at  times  encroached  upon  by 
recess  extensions  of  the  frontal  sinuses ;  moreover,  a  cell  in  the  crista 
galli  may  impinge  upon  it  (Fig.  200). 

A  number  of  strata  may  be  distinguished  surrounding  the  central 
core  of  the  olfactory  bulb:  (a)  the  superficial  non-medullated  nerve-fiber 
layer  which  rests  on  the  cribriform  plate  of  the  ethmoid,  the  fibers  being 
the  axons  of  the  bipolar  olfactory  cells  of  the  olfactory  nasal  mucous  mem- 
brane; (b)  the  layer  of  the  olfactory  glomeruli;  (c)  the  superficial  plexi- 
form  layer;  (d)  the  stratum  of  mitral  cells;  (e)  the  deep  plexiform  layer; 
(f)  the  granule  layer;  and  (g)  the  layer  of  deep  nerve  fibers,  composed  of 
both  afferent  and  efferent  elements.  As  stated  elsewhere,  the  central 
cavity  (ventriculus  bulbi  olfactorii)  is  obliterated  in  man  and  filled  by  a 
modified  neuroglia. 

The  olfactory  tract  is  a  narrow,  more  or  less  triangular  band  of  white 
substance  which  arises  in  the  olfactory  bulb  and  courses  dorsalward  for 
a  distance  of  from  1 8  to  20  mm.  to  the  anterior  perforated  space  where  it 
undergoes  a  flattening  and  widening.  Despite  the  rudimentary  nature 
of  the  olfactory  tract  in  man  three  strata  can  be  demonstrated :  (a)  a  longi- 
tudinally directed  stratum  of  nerve  fibers;  (b)  a  modified  neurogliar  or 
gelatinous  stratum,  occupying  the  former  ventriculus  tracti  olfactorii; 
and  (c)  a  dorsal  stratum  of  gray  substance,  in  reality  a  remnant  of  the 
cortical  gray  matter  from  which  fibers  pass  to  other  parts. 


OLFACTORY  BRAIN 


331 


The  olfactory  tract  ends  as  such  in  the  neighborhood  of  the  olfactory 
trigone  (vide  infra)  by  dividing  into  the  olfactory  strice  or  gyri:  (a)  the 
medial  stria,  (b)  the  lateral  stria,  and  (c)  the  less  definite  intermediate 
stria.  The  lateral  stria  courses  across  the  lateral  portion  of  the  anterior 
perforated  substance  and  bends  sharply  medialward  to  enter  the  uncus. 
A  few  of  the  fibers  of  the  lateral  stria  penetrate  the  olfactory  trigone  and 
equally  few  terminate  in  the  anterior  perforated  substance.  The  medial 
stria  bends  medialward  and  its  fibers  terminate  largely  in  the  parolf  actory 
area  of  Broca;  relatively  few  terminate  in  the  subcallosal  gyrus  and  the 
anterior  perforated  space  and  adjacent  parts  of  the  septum  pellucidum. 
Some  of  the  fibers  of  the  medial  stria  form  the  pars  olfactoria  of  the  anterior 
commissure  which  connects  the  olfactory  bulbs  of  the  two  sides.  The 
intermediate  stria  is  but  little  elevated  above  the  surface,  indeed  not  in- 
frequently is  scarcely  visible  to  the  naked  eye.  Its  fibers  terminate  for 
the  most  part  in  the  anterior  perforated  space ;  a  few  pass  beyond  to  the 
uncus. 

The  further  connections  of  the  fibers  of  the  olfactory  striae  will 
be  discussed  subsequently. 

The  olfactory  trigone  or  tubercle  (trigonum  olfactorium)  is  a  small 
elevated  triangular  area  immediately  ventral  to  the  anterior  perforated 
space  with  its  apex  directed  forward  and  projecting  slightly  into  the  dorsal 
extremity  of  the  olfactory  sulcus.  The  olfactory  tract  in  a  sense  merges 
with  the  olfactory  triangle,  however,  few  of  its  component  fibers  actually 
terminate  about  cell  bodies  within  the  substance  of  the  triangle. 

The  anterior  perforated  substance  (substantia  perforata  anterior) 
comprises  the  basal  region  limited  by  the  optic  chiasma  and  tract  arid 
the  olfactory  trigone  and  in  large  part  belongs  to  the  rhinencephalon. 
The  fissura  prima  separates  the  olfactory  trigone  from  the  anterior  per- 
forated substance.  Ventrally  and  medially  the  anterior  perforated 
substance  is  confluent  with  the  subcallosal  gyrus,  and  laterally  is  found 
the  lateral  olfactory  stria  on  its  way  into  the  uncus  and  the  limen  insula. 
Moreover,  the  gray  matter  of  the  anterior  perforated  substance  is  con- 
fluent with  the  corpus  striatum.  Numerous  blood  vessesls  enter  the  sub- 
stance giving  it  the  perforated  appearance.  Some  fibers  from  the  ol- 
factory tract  end  about  cell  bodies  located  within  the  anterior  perforated 
substance  (vide  supra). 

The  parolfactory  area  of  Broca  (area  parolfactoria)  is  particularly 
related  to  the  medial  stria  of  the  olfactory  tract,  since  many  of  the 
latter  fibers  terminate  in  it.  It  is  a  small,  more  or  less  triangular  field 
located  on  the  medial  surface  of  the  cerebral  hemisphere  immediately 


332 


THE  OLFACTORY  APPARATUS  PROPER 


I 


£  ^  u. 


OLFACTORY  BRAIN  333 

in  front  of  the  subcallosal  gyrus,  the  posterior  parolfactory  sulcus  inter- 
vening. Ventrally  the  parolfactory  area  is  delimited  by  the  anterior 
parolfactory  sulcus  (Fig.  203).  The  parolfactory  area  is  grossly  con- 
fluent with  the  olfactory  trigone  and  the  cingulate  gyrus  (gyrus  cinguli). 

The  subcallosal  gyrus  (gyrus  subcallosus;  peduncle  of  corpus  cal- 
losum)  is  a  narrow  band  or  lamina  of  the  pallium  found  on  the  medial 
surface  of  the  cerebral  hemisphere  just  in  front  of  the  rostral  lamina 
(lamina  rostralis)  and  the  terminal  lamina  (lamina  terminalis);  behind 
the  parolfactory  area  of  Broca;  and  below  the  rostrum  of  the  corpus 
callosum.  It  is  more  or  less  fused  above  to  the  rostrum  and  is  continuous 
around  the  genu  of  the  corpus  callosum  with  the  supracallosal  gyrus  and 
to  some  extent  with  the  cingulate  gyrus.  Ventrally  the  subcallosal  gyrus 
in  part  passes  laterodorsally  on  its  way  into  the  uncus  and  in  doing  so 
courses  in  a  portion  of  the  anterior  perforated  substance  usually  referred 
to  as  the  diagonal  band  of  Broca.  The  right  and  left  subcallosal  gyri 
are  closely  approximated  in  the  mid-sagittal  plane,  the  median  subcallosal 
sulcus  ofRetzius  alone  intervening.  As  stated  else  where,  a  few  of  the  fibers 
of  the  median  olfactory  stria  terminate  about  cell  bodies  within  the  sub- 
callosal gyrus,  others  may  course  through  it  without  synapse. 

The  supracallosal  gyrus  (gyrus  epicallosus;  stratum  griseum)  con- 
sists of  a  very  delicate  sheet  of  gray  substance  in  immediate  gross  contact 
with  the  upper  surface  of  the  corpus  callosum,  laterally  it  merges  with 
the  cingulate  gyrus,  and  ventrally  it  is  continued  as  the  subcallosal  gyri 
(vide  supra). 

Three  longitudinal  strice  (striae  longitudinales)  are  the  most  con- 
spicuous portions  of  the  supracallosal  gyrus,  e.g.,  the  medial  and  lateral 
longitudinal  strice.  Dorsally  the  thin  supracallosal  lamina  with  its 
striae  passes  around  the  splenium  of  the  corpus  callosum  and  continues 
bilaterally  as  the  fasciola  cinerea,  then  as  the  fascia  dentata  hippocampi 
(Fig.  203).  Some  of  the  component  fibers  of  the  supracallosal  gyrus 
arise  from  cell  bodies  located  within  the  subcallosal  gyrus,  the  parol- 
factory area  of  Broca,  and  the  anterior  perforated  substance.  These 
fibers  assume  a  dorsal  course  within  the  longitudinal  striae  and  terminate 
in  the  dentate  fascia  and  the  hippocampal  field.  Other  fibers  leave  the 
gray  matter  of  the  supracallosal  gyrus  and  enter  the  longitudinal  striae, 
coursing  both  forward  and  backward.  A  few  of  the  component  fibers 
of  the  striae  are  known  to  pierce  the  corpus  callosum  to  join  the  fornix 
(see  page  332). 

The  fascia  dentata  hippocampi  (gyrus  dentatus)  is  prolonged  from 
the  fasciola  cinerea  caudoventralward    above    the   hippocampal  gyrus 


334  THE  OLFACTORY  APPARATUS  PROPKR 

into  the  depression  of  the  uncus  where  it  forms  an  acute  bend  and  is 
continued  over  the  surface  of  the  uncus  for  a  greater  or  less  distance  as  the 
band  of  Giacomini.  The  identity  of  the  latter  is  ultimately  lost  on  the 
lateral  surface  of  the  uncus.  The  free  edge  of  the  dentate  fascia  or  gyrus 
is  overlapped  by  the  fimbria,  the  fimbriodentate  fissure  intervening,  and 
presents  a  characteristic  notched  appearance,  the  result  of  many  parallel 
grooves  partially  cutting  it  at  right  angles  (Fig.  203).  Below  the  dentate 
fascia  or  gyrus  is  the  extremely  rudimentary  or  in  most  cases  obliterated 
hippocampal  or  dentate  fissure.  The  latter  is  not  a  factor  in  the  produc- 
tion of  the  hippocampus  in  man  (vide  infra). 

The  hippocampus  (hippocampus  major)  is  the  curved,  sickle-shaped 
ventricular  eminence,  about  5  cm.  long,  which  courses  throughout  the 
length  of  the  floor  of  the  inferior  cornu  of  the  lateral  ventricle.  It 
begins  as  a  narrow,  low  ridge  dorsally  at  the  termination  of  the  body  of 
the  lateral  ventricle  where  it  is  confluent  with  the  posterior  pillar  of  the 
fornix.  Ventrally  and  inferiorly  the  hippocampus  undergoes  enlarge- 
ment forming  the  ventricular  surface  of  the  uncus  and  presents  from  two 
to  three  secondary  elevations,  the  hippocampal  digitations.  This  causes  a 
paw-like  conformation,  the  pes  hippocampi. 

The  hippocampus  is  covered  by  a  thick  layer  of  white  substance — 
the  alveus — which  arises  from  deeper  parts  and  is  continued  medially 
to  become  confluent  with  ihefimbria  hippocampi.  The  latter  is  folded, 
and  its  margin — the  tcenia  fimbrice,  lies  in  a  sense  in  the  cavity  of  the 
inferior  cornu  and  attached  to  the  choroid  plexus  and  the  extremely 
delicate  non-nervous  floor  of  the  choroidal  fissure.  It  should,  however, 
be  recalled  that  the  immediate  boundary  of  the  inferior  cornu  of  the  lateral 
ventricle  is  epithelium  (ependyma)  and  that,  strictly  speaking,  the  only 
thing  in  the  ventricular  system  is  the  cerebrospinal  fluid. 

The  ventricular  eminence  (hippocampus)  in  man  is  formed  by  the 
hippocampal  and  dentate  columns  of  cells  pushing  the  ventricular  sur- 
face into  relief  rather  than  by  an  invagination  of  the  surface,  usually 
referred  to  as  the  fissura  hippocampi.  Elliot  Smith  says:  "There  is  no 
fissura  hippocampi  in  the  human  brain."  While  this  is  true  in  the  ma- 
jority of  specimens  there  are  occasional  partial  hippocampal  fissures  en- 
countered but  seldom  of  sufficient  depth  to  be  a  factor  in  the  molding  of 
the  hippocampus. 

The  uncus  appears  as  the  thickened  ventral  extremity  of  the  hippo- 
campal gyrus,  and  ventrally  and  caudally  is  separated  from  the  adjacent 
temporal  lobe  by  the  rhinal  .sulcus.  Deeply  the  uncus  is  in  juxtaposition 
to  the  anterior  perforated  substance,  and  as  stated  elsewhere,  is  connected 


OLFACTORY  BRAIN  335 

dorsally  and  medially  with  the  fascia  dentata  hippocampi  and  the  fimbria 
hippocampi.  Moreover,  the  lateral  olfactory  stria  in  large  measure 
ends  in  the  uncus  (vide  supra).  Despite  the  fact  that  the  uncus  is 
seemingly  a  part  of  the  limbic  lobe,  in  continuity  with  the  hippocampal 
gyrus,  Turner  and  Elliot  Smith  have  established  its  relation  with  the 
rhinencephalon. 

The  fornix  is  the  great  bilateral  association  pathway,  arched  beneath 
the  corpus  callosum  and  confluent  with  the  septum  lucidum.  It  is 
concerned  almost  wholly  with  the  rhinencephalon.  It  may  be  considered 
the  chief  fiber-pathway  connecting  the  olfactory  cortex  located  within 
the  uncus  and  hippocampus  with  the  habenular  body  of  the  epithalamus, 
the  mammillary  body  of  the  hypothalamus,  and  secondarily  with  the 
thalamus  and  mid-brain.  Moreover,  the  angle  formed  by  the  diverging 
posterior  pillars  (crura  fornices)  with  the  body  of  the  fornix  is  crossed  by 
the  transverse  fibers — the  transverse  fornix  or  the  hippocampal  com- 
missure— whereby  the  right  and  left  hippocampal  regions  are  intercon- 
nected. Not  infrequently  the  dorsal  part  of  the  body  of  the  fornix 
and  the  transverse  fornix  are  adherent  to  the  under  surface  of  the  corpus 
callosum;  again,  a  horizontal  cleft,  the  so-called  ventricle  of  the  fornix 
( Verga's  ventricle) ,  may  intervene.  The  crura  or  posterior  pillars  of  the 
fornix  are  continued  into  the  inferior  cornua  of  the  lateral  ventricle  as 
the  fimbria  hippocampi  (see  page  334).  The  anterior  pillars  end  as 
such  in  the  mammillary  bodies  of  the  hypothalamus,  however,  many  of 
the  fibers  pass  through  them  without  termination  in  synapses,  decussate 
to  the  opposite  side,  turn  into  the  reticular  formation  and  course  to 
the  mid-brain,  pons,  and  probably  to  lower  levels  (see  also,  the  tractus 
mammillopeduncularis,  page  342).  It  is  not  deemed  profitable  in  this 
connection  to  enter  into  a  detailed  description  of  the  fornix.  The  fore- 
going will  suffice  to  indicate  the  connections  of  the  fornix  as  an  important 
association  pathway  in  the  olfactory  apparatus. 

The  septum  pellucidum  (septum  lucidum)  is  the  thin,  vertical  bi- 
laminar  partition  between  the  anterior  cornua  of  the  lateral  ventricles. 
It  is  attached  above  to  the  under  surface  of  the  corpus  callosum,  below 
and  dorsally  to  the  fornix,  and  ventrally  to  the  reflected  portion  of  the 
corpus  callosum  (Fig.  203).  The  septum  pellucidum  contains  between 
its  laminae  the  cavum  septi  pellucidi — the  so-called  fifth  ventricle.  Each 
lamina  of  the  septum  consists  of  a  stratum  of  degenerated  gray  matter 
next  the  cavity  of  the  septum  and  a  stratum  of  white  matter  next  the 
ependyma  of  the  anterior  cornu  of  the  lateral  ventricle. 

The  septum  pellucidum  is  in  part  concerned  with  the  olfactory  organ. 


336  THE  OLFACTORY  APPARATUS  PROPER 

Some  of  the  fibers  of  the  supracallosal  gyrus  join  the  fornix  ventrally 
by  passing  through  the  ventral  and  inferior  part  of  the  septum  pellucidum. 
Moreover,  a  few  fibers  from  the  medial  olfactory  stria  pass  into  the  septum 
pellucidum  and  course  by  way  of  the  fornix  to  the  hippocampus.  It 
appears  that  the  posterior  angle  of  the  septum  pellucidum  contains  a 
few  commissural  fibers  which  leave  the  body  of  the  fornix  and  a  few 
perforating  fibers  which  come  from  higher  levels,  e.g.,  from  the  stratum 
griseum  and  fasciculus  cinguli.1 

The  habenular  triangle  (trigonum  habenulae)  is  the  small  triangular 
area  delimited  by  the  superior  collicular  body,  the  peduncle  of  the  pineal 
body,  and  the  pulvinar  of  the  thalamus.  This  triangle  contains  the 
habenular  ganglion  (ganglion  habenulae) — an  important  olfactory  reflex 
center.  About  the  cell  bodies  terminate  the  fibers  of  the  medullary 
stria?  of  the  thalami  of  the  same  and  opposite  sides,  the  decussation  taking 
place  by  way  of  the  habenular  commissure.  The  axons  of  the  cells  of  the 
habenular  ganglion  are  collected  on  the  ventral  aspect  of  the  ganglion  and 
give  rise  to  the  fasciculus  retroflexus  of  Meynert  which  courses  down- 
ward and  forward  in  the  tegmentum  of  the  mid-brain,  medial  to  the  red 
nucleus,  and  ends  as  such  by  synapsing  with  cell  bodies  within  the  inter- 
peduncular  ganglion.  The  axons  of  the  cell  bodies  of  the  latter  ganglion 
form  the  tegmental  bundle  of  Gudden  which  partly  ends  in  the  dorsal 
tegmental  nucleus.  The  fibers  of  the  bundle  also  establish  relationships 
with  Schutz's  dorsal  longitudinal  bundle  and  with  other  association  neur- 
ons in  the  neighborhood. 

The  medullary  stria  of  the  thalamus  (stria  medullaris  thalami) 
is  a  bilateral  band  of  nerve  fibers  which  courses  along  the  superomedial 
aspect  of  the  thalamus  subjacent  to  the  ependymal  ridge — the  tcenia 
thalami.  Many  of  the  fibers  of  the  medullary  stria  end  by  synapsing 
with  cell  bodies  within  the  habenular  ganglion  of  the  same  side,  others 
decussate  in  the  habenular  commissure  and  end  by  synapsing  with  cell 
bodies  within  the  habenular  ganglion  of  the  opposite  side.  Moreover,  it 
is  believed  that  a  few  component  fibers  of  the  medullary  stria  fail  of  termi- 
nation within  the  habenulae  and  pass  as  such  into  the  superior  colliculus 
of  the  mid-brain,  others  into  the  posterior  longitudinal  bundle.  Relation- 
ships are  also  established  with  association  neurons  of  the  midbrain. 

1  The  cingulum  (fasciculus  cinguli)  is  an  association  pathway  which  begins  in  front  in  the  vicinity 
of  the  anterior  perforated  substance,  arches  in  front  of,  then  over  the  corpus  callosum  to  the  splenium 
of  the  latter,  where  it  curves  forward  and  downward  in  relation  with  the  hippocampal  gyrus,  the 
uncus,  and  the  temporal  lobe.  The  cingulum  is  contained  within  the  basal  part  of  the  cingulate 
gyrus  and  is  composed  of  a  number  of  short  tracts,  which  enter  and  leave  it  at  short  intervals.  It 
is  established  that  no  long  association  fibers  coursing  the  entire  extent  of  the  cingulum  are  present. 


OLFACTORY  BRAIN 


337 


The  majority  of  the  component  fibers  of  the  medullary  stria  of  the 
thalamus  belong  to  the  olfactory  apparatus  and  are  derived  from  three 
important  sources:  (a)  fibers  from  the  anterior  perforated  substance  and 
the  parolfactory  area  of  Broca  pass  to  the  medullary  stria  and  form  a 
rather  direct  olfacto-habenular  tract;  (b)  fibers  from  cell  bodies  within 
the  anterior  nucleus  of  the  thalamus  bend  into  the  medullary  stria,  forming 
a  thalamo-habenular  pathway;  and  (c)  fibers  leave  the  fornix  and  recurve 
into  the  medullary  stria.  These  fibers  are  axons  of  nerve  cell  bodies  within 

Gyms  supracattosus 
, Fascivla.  cinerecL, 


Corpu-S 


Ftzscia.  deutaJa  hippocampi    \  ^^-^ 


FIG.  203.  —  A  dissection  showing  the  rhinencephalon  or  olfactory  brain  in  color.  A  goodly  portion 
of  the  thalamus  is  removed  and  other  portions  of  the  brain  drawn  aside  so  as  to  expose  the  fimbria, 
hippocampus,  etc. 

Ca  =  Commissura  anterior;  Smt  =  Stria  medullaris  thalami;  Fmt  =  Fasciculus  mammillo- 
thalamicus  (Vicq  d'  Azyr). 

The  inset  in  the  lower  right  hand  corner  is  a  frontal  section  from  the  lower  end  of  the  inferior  horn 
of  the  lateral  ventricle  and  related  structures. 

i  =  Choroidal  fissure;  2  =  Fimbria;  3  =  Fimbrio-dentate  fissure;  4  =  Rudimentary  hippocampal 
fissure;  5  =  Dentate  gyrus;  6  =  Hippocampus;  7  =  Inferior  horn  of  lateral  ventricle;  8  =  Tenia 
semicircularis;  9  =  Tail  of  caudate  nucleus;  10  =  Choroid  plexus;  n  =  Ependymal  lining  investing 
the  choroid  plexus  and  lining  the  horn  of  the  ventricle. 

the  hippocampus  and  uncus.     They  are  often  referred  to  as  the  cortico- 
habenular  tract  (Fig.  202). 

The  mammillary  bodies  (copora  mammillaria)  are  the  round,  white 
bodies  which  lie  side  by  side  in  the  interpeduncular  fossa,  behind  the  stalk 


338  THE  OLFACTORY  APPARATUS  PROPER 

of  the  hypophysis  and  immediately  in  front  of  the  posterior  perforated 
substance.  The  bodies  have  an  ectal  covering  of  white  substance  largely 
derived  from  the  columns  of  the  fornix,  and  their  interiors  contain  gray 
nuclei  with  many  cells.  The  mammillary  bodies  have  important  olfac- 
tory connections;  e.g.,  the  columns  of  the  fornix,  the  fasciculus  mammillo- 
thalamicus  and  the  fasciculus  mammillopeduncularis.  Through  some  of 
these  paths  olfactory  impulses  reach  the  brain  stem  and  probably  the 
spinal  cord,  thereby  influencing  the  skeletal  muscles. 

The  stria  terminalis  (taenia  semicircularis)  is  a  bilateral  narrow, 
ribbon-like  band  of  white  substance  located  in  the  sulcus  between  the 
caudate  nucleus  and  the  thalamus  and  according  to  Dejerine  is  connected 
with  the  olfactory  sense.1  Both  the  anterior  perforated  space  and  the 
septum  pellucidum  yield  fibers  to  the  stria.  It  is  also  believed  that  the 
anterior  cerebral  commissure  adds  a  few  components  to  it  from  the  opposite 
olfactory  lobe.  Most  of  the  fibers  of  the  stria  terminalis  continue  dor- 
sally  in  the  interval  between  the  caudate  nucleus  and  the  thalamus,  leave 
the  body  of  the  lateral  ventricle  and  descend  within  the  roof  of  the  inferior 
cornu  of  the  same  and  in  intimate  topographic  relationship  with  the  tail 
of  the  caudate  nucleus  to  terminate  in  the  amygdaloid  nucleus  (nucleus 
amygdalae).  Moreover,  the  stria  terminalis  contains  fibers  which  arise 
from  cell  bodies  located  within  the  amygdaloid  nucleus.  These  fibers 
oppose  the  others  as  regards  direction,  and  after  coursing  for  a  greater  or 
less  distance  as  components  of  the  stria  they  pass  (a)  to  the  thalamus  and 
(b)  to  the  internal  capsule  and  cerebral  cortex. 

The  amygdaloid  nucleus  is  located  in  the  ventral  portion  of  the  tem- 
poral lobe  and  in  most  intimate  topographic  relationship  with  the  uncus. 
Indeed,  the  nucleus  appears  to  be  a  detached  portion  of  the  uncus. 

Olfactory  Reflex  and  Cortical  Connections. — As  previously  stated 
the  cell  bodies  of  the  olfactory  neurons  of  the  first  order  are  located  in  a 
small  area  of  the  nasal  mucous  membrane.  The  axons  or  central  processes 
of  these  neurons  pass  through  the  cribriform  plate  of  the  ethmoid  bone  in 
approximately  twenty  bundles  (the  olfactory  nerves,  collectively  the  ol- 
factory nerve),  and  terminate  by  free  arborizations  in  the  primary  ol- 
factory center  (reception  nucleus)  within  the  olfactory  bulb.  As  a  rule, 
several  olfactory  nerve  fibers  and  one  or  more  dendrites  of  the  mitral  cells 
form  entanglements  of  fibers  known  as  the  olfactory  glomeruli.  Here  the 
first  synapse  in  the  olfactory  pathway  occurs  (Fig.  202). 

The  arrangement  of  the  neurons  and  their  mode  of  synapse  within 
the  olfactory  bulb  may  lead  to  strong  excitations  in  the  olfactory  centers 

1  The  stria  terminalis  is  not  infrequently  referred  to  purely  as  an  association  pathway. 


OLFACTORY  REFLEX  AND  CORTICAL  CONNECTIONS  339 

even  though  the  peripheral  olfactory  stimulation  be  feeble.  As  shown  in 
the  diagram  (Fig.  202),  two  or  more  olfactory  nerve  fibers  may  synapse 
with  the  dendrites  of  a  single  mitral  cell,  thus  providing  for  the  summation 
of  stimuli  in  a  single  mitral  cell.  Furthermore,  in  addition  to  forming 
component  fibers  of  the  olfactory  tract,  the  axons  of  the  mitral  cells  give 
off  collateral  branches  which  synapse  with  the  granule  cells  (small  neurons 
of  the  olfactory  bulb),  which  granule  cells  discharge  among  the  dendrites 
of  the  mitral  cells.  This  arrangement  causes  the  discharge  from  the  mitral 
cells  to  be  enhanced. 

The  mitral  cells  are  of  the  second  order  in  the  olfactory  neuron  chain, 
and,  as  stated  above,  their  central  processes  (axons)  collectively  form  the 
olfactory  tract.  The  latter  extends  dorsally  and  divides  into  three  dis- 
tinct paths,  the  medial,  intermediate,  and  lateral  olfactory  striae,  to 
terminate  in  various  portions  of  the  olfactory  area  or  the  secondary  ol- 
factory center  and  at  points  beyond. 

The  medial  olfactory  stria  curves  medially  and  most  of  its  component 
fibers  terminate  about  cell  bodies  located  within  the  parolfactory  area  of 
Broca.  Relatively  few  fibers  are  found  to  end  within  the  substance  of 
the  anterior  perforated  space  and  the  related  portions  of  the  septum 
pellucidum.  Moreover,  it  is  well  established  that  the  right  and  left 
olfactory  bulbs  are  connected,  the  fibers  of  communication  coursing  by 
way  of  the  medial  olfactory  stria  and  decussating  in  the  anterior  cerebral 
commissure,  forming  its  pars  olfactoria  (see  also  page  343). 

The  lateral  olfactory  stria  is  the  particularly  prominent  root  of  the 
olfactory  tract,  receiving  most  of  its  fibers.  This  stria  is  not  infrequently 
referred  to  as  the  lateral  olfactory  gyrus.  It  curves  dorsolateralward 
and  its  component  fibers  cross  the  anterolateral  portion  of  the  anterior 
perforated  space  into  which  a  few  fibers  sink  to  terminate  about  its  cell 
bodies.  Equally  few  fibers  find  their  termination  in  the  olfactory  tri- 
gone.  The  vast  majority  of  the  fibers  of  the  lateral  olfactory  stria,  how- 
ever, pass  beyond  and  penetrate  the  uncus  to  establish  synapse  relations 
with  cell  bodies  found  within  this  complicated  and  chief  olfactory  cortical 
region.  Moreover,  the  component  fibers  of  the  lateral  olfactory  stria  in 
coursing  over  the  subfrontal  region  on  their  way  to  the  uncus,  give  off 
collaterals  which  establish  synapse  relations  with  cells  of  the  related 
frontal  cortex.  The  latter  cells  give  off  axons  to  the  medullary  stria  of 
the  thalamus  and  to  the  thalamus.  Some  of  these  fibers  may  reach  the 
brain  stem  (pons  and  medulla). 

The  intermediate  olfactory  stria  is  the  most  indefinite  of  the  roots  of 
the  olfactory  tract.  Most  of  its  component  fibers  terminate  within  the 


340  THE  OLFACTORY  APPARATUS  PROPER 

anterior  perforated  substance,  while  a  few  are  doubtless  prolonged  beyond 
into  the  olfactory  cortex  (uncus). 

The  several  nuclei  of  the  secondary  olfactory  center  (the  primary  ol- 
factory center  is  located  in  the  olfactory  bulb)  are  (i)  important  reflex 
centers  where  olfactory  and  other  sensory  impulses  are  correlated  and  (2) 
centers  for  the  discharge  of  olfactory  impulses  into  the  olfactory  cerebral  cortex. 
It  is  believed  that  each  nucleus  of  the  olfactory  area  has  an  individual 
physiologic  pattern  complex.  Ludwig  Edinger  believes  that  the  inter- 
mediate nucleus,  for  example,  especially  in  some  mammals,  is  concerned 
with  the  feeding  reflexes  of  the  muzzle  or  snout;  including,  therefore,  touch, 
smell,  taste,  and  muscle  and  tendon  sensibility.  To  this  function  complex 
Edinger  has  applied  the  term  "oral  sense."  The  reader  is  referred  to  the 
appended  works  by  Edinger1  for  full  discussions.  It  would  lead  us  too 
far  afield  to  consider  them  here. 

From  the  several  portions  of  the  secondary  olfactory  center  go  forth 
neuron  pathways  of  the  third  order,  some  more  or  less  direct,  others  tor- 
tuous, involved  in  olfactory  reflexes  and  in  carrying  impulses  destined  to 
reach  the  olfactory  cortical  centers.  Moreover,  many  fibers  of  the  ol- 
factory tract  pass  the  secondary  olfactory  center  without  suffering  termi- 
nation in  synapses,  particularly  those  coursing  via  the  lateral  olfactory  stria. 

The  reflex  pathways  from  the  secondary  olfactory  centers  within  the 
olfactory  area,  etc.,  pass  in  large  measure  to  the  mammillary  bodies 
of  the  hypothalamus  and  the  habenular  bodies  of  the  epithalamus.  From 
these  bodies  issue  neurons  of  the  fourth  order  to  connect  with  the  motor 
centers  of  the  brain  stem,  which  in  turn  establish  relations  with  the  nuclei 
of  origin  of  cranial  nerves  and  seemingly  with  the  ventral  horn  cells  of  the 
upper  spinal  cord  as  well.  Through  these  relations  the  most  varied  reflex 
movements  are  accomplished  following  olfactory  excitation.  The  studies 
of  Herrick2  have  led  him  to  believe  that  in  the  epithalamus  the  olfactory 
nervous  impulses  are  correlated  with  those  of  the  somatic  sensory  centers 
of  the  thalamus  (optic  thalamus),  especially  the  optic  and  the  tactual 
systems;  while  in  the  hypothalamus  they  are- correlated  with  the  gustatory 
and  the  various  visceral  (sympathetic)  sensory  systems.  Moreover,  as 

1  Vorlesungen  uber   Bau   der  nervosen   Zentralorgane  Vergleichende  Anatomic   des   Gehirns, 
Leipzig,  Bd.  2,  1908. 

The  Relations  of  Comparative  Anatomy  to  Comparative  Psychology,  Journal  Comparative 
Neurology,  Vol.  XVIII,  pp.  437-457,  1908. 

Ueber  die  Oralsinne  dienenden  Apparate  am  Gehirn  der  Sauger,  Deutsch.  Zeits.  f.  Xerven- 
heilkunde,  Bd.  36,  1908. 

Vorlesungen  uber  den  Bau  der  Xervosen  Zentralorgane  Des  Menschen  und  der  Tiere,  Leipzig, 
1911. 

2  Introduction   to  Xeurology,  Philadelphia,  1916. 


IMPORTANT  OLFACTORY  PATHWAYS  341 

stated  above,  the  secondary  olfactory  center  discharges  also  into  the  ol- 
factory cerebral  cortex,  the  hippocampus  and  uncus. 

The  olfactory  cortical  centers  give  off  association  pathways  for  connec- 
tion with  other  parts  of  the  cerbral  cortex,  thus  bringing  the  varied  func- 
tional systems  into  interrelation  with  olfaction.  Moreover,  from  the  olfac- 
tory cortex,  especially  the  hippocampus,  issues  a  motor  (efferent)  pathway 
which  courses  by  way  of  the  fimbria,  the  several  portions  of  the  fornix  and 
the  striae  medullares  thalami  to  reach  both  the  hypothalamus  and  the 
epithalamus.  From  the  latter  points  connections  are  established  with  the 
motor  center  in  the  cerebral  peduncles,  etc.,  by  the  same  pathways  that 
are  involved  in  olfactory  reflexes.  Efferent  or  motor  impulses  (of  cortical 
origin)  in  which  the  olfactory  element  prevails  follow  the  efferent  neuron 
pathway  from  the  olfactory  cortex  above  referred  to,  and  by  projection 
and  association  pathways  reach  the  motor  centers  in  the  cerebral  peduncles 
within  the  mid-brain,  the  nuclei  of  origin  of  the  several  cranial  nerves,  and 
the  cell  bodies  of  the  motor  spinal  nerves  located  in  the  ventral  horns. 
Such  acts  as  motions  of  the  alae  of  the  nose,  sniffing,  turning  the  head  and 
body  aside  when  breathing  unpleasant  and  irritating  odors  may  be  ex- 
plained by  such  neuron  pathways.  Obviously,  it  is  at  times  difficult 
to  separate  actions  which  are  the  result  of  olfactory  reflexes  from  volun- 
tary motor  actions  resulting  from  efferent  impulses  in  which  the  olfactory 
element  predominates. 

Olfactory  Pathways. — The  more  important  connections  of  the  ol- 
factory apparatus  may  be  briefly  summed  up  as  follows  (Fig.  202): 

(A)  An  afferent  conduction  path  conveys  olfactory  impulses  from  the 
olfactory  mucous  membrane  to  the  primary  olfactory  center  located  within 
the  olfactory  bulb.     From  here  the  impulses  follow  the  olfactory  tract 
and  either  pass  directly  to  the  olfactory  cortical  centers  or  are  transferred, 
within  the  secondary  olfactory  center,  to  neurons  of  the  third  order,  the 
axons  of  which  likewise  terminate  in  the  olfactory  cortex.     It  will  be  re- 
called that  the  greater  number  of  the  axons  of  the  mitral  cells  after  cours- 
ing in  the  olfactory  tract  are  prolonged  into  the  lateral  olfactory  stria  and 
terminate  in  the  uncus,  a  few  axons  terminating  within  the  olfactory 
trigone  and  the  anterior  perforated  substance.     While  the  uncus  and  the 
hippocampus  contain  the  important  cortical  centers  for  smell,  the  amygda- 
loid nucleus  also  is  believed  to  be  part  of  the  olfactory  cortex.     It  is  con- 
nected with  the  secondary  olfactory  center  by  the  tract  known  as  the  stria 
terminalis  or  taenia  semicircularis  (see  page  338). 

(B)  The  several  portions  of  the  secondary  olfactory  center  are  im- 
portant  olfactory  reflex   stations.     Tracts  arising  from   the   secondary 


342  THE  OLFACTORY  APPARATUS  PROPER 

center  pass  directly  to  the  tuber  cinereum,  the  mammillary  body,  the 
habenular  ganglion,  the  brain  stem,  and  in  all  probability  the  spinal  cord. 
While  the  reflex  paths  from  the  secondary  olfactory  center  to  the  lower 
portions  of  the  brain  stem  and  spinal  cord  are  but  partially  known,  the 
following  tracts  appear  established: 

1.  The  direct  tractus  olfactotegmentalis   (tractus  olfactomesencephali- 
cus,  basal  olfactory  bundle  of  Wallenburg)  arises  from  cell  bodies  located 
within  the  anterior  perforated  substance,  the  olfactory  trigone,  the  cortex 
of  the  olfactory  tract,  and  the  septum  pellucidum.     The  tract  courses  more 
or  less  direct  to  the  tuber  cinereum,  the  mammillary  body,  the  motor  centers 
of  the  brain  stem,  and,  according  to  some  investigators,  to  the  spinal  cord. 
Some  of  the  fibers  of  the  olfactotegmental  tract  penetrate  the  mammillary 
body  and  are  believed  to  establish  relationships  with  the  contained  nerve 
cell  bodies,  the  latter  giving  rise  to  the  tractus  mammillopeduncularis. 

2.  The  tractus  mammillopeduncularis  (fasciculus  mammillotegmen- 
talis,  the  mammillotegmental  bundle  of  Gudden)  connects  the  mammillary 
body  with  the  motor  centers  of  the  mid-brain  within  the  cerebral  peduncles 
and  the  gray  substance  of  the  cerebral  aqueduct.     Moreover,  a  few  fibers 
of   the   mammillopeduncular   tract   are  believed  to  enter  the  posterior 
longitudinal  bundle. 

3.  The  tractus  olfactohabenularis  arises  from  cell  bodies  located  within 
the  parolfactoiy  area  and  the  anterior  perforated  substance  and  passes 
through  the  inferior  segment  of  the  septum  pellucidum,  and  with  other 
fibers  (tractus  corticohabenularis,  etc.)  forms  the  stria  medullaris  thalami 
(see  page  337  for  the  component  fibers  of  this  stria).     The  medullary  stria 
of  the  thalamus  terminates  by  synapses  in  the  habenular  nucleus  of  the 
same  and  opposite  sides  (see  page  336).     Moreover,  it  is  known  that  a 
few  fibers  of  the  medullary  stria  fail  of  termination  within  the  habenular 
nucleus  and  continue  beyond  into  the  superior  collicular  (quadrigeminal) 
body  and  the  association  and  projection  pathways  of  the  mid-brain,  in- 
cluding the  posterior  longitudinal  bundle. 

4.  The  tractus  habenulopeduncularis  (fasciculus  retroflexus,  Meynert's 
bundle)  issues  from  the  cell  bodies  of  the  habenular  nucleus  and  connects 
the  latter  with  the  interpeduncular  ganglion  located  within  the  posterior 
perforated  substance  in  front  of  the  pons  between  the  cerebral  peduncles. 

5.  The  tractus  tegmentalis  (tegmental  bundle  of  Gudden)  arises  from 
the  cell  bodies  of  the  interpeduncular  nucleus,  courses  dorsocaudalward 
and  some  of  its  fibers  end  in  the  red  nucleus,  others  come  into  relationship 
with  Schutz's  dorsal  longitudinal  bundle  and  other  association  neurons 
of  the  tegmentum  of  the  mid-brain. 


IMPORTANT  OLFACTORY  PATHWAYS  343 

6.  The  tractus  mammillothalamicus  (tract  of  Vicq  d'Azyr)  connects 
the  mammillary  body  with  the  anterior  nucleus  of  the  thalamus  for  the 
correlation  of  the  olfactory  with  the  general  somatic  reactions.  The  tract 
of  Vicq  d'Azyr  is  formed  by  axons  arising  from  the  cell  bodies  of  the  medial 
and  lateral  nuclei  of  the  mammillary  body  and  by  some  of  the  fibers  con- 
tinued from  the  anterior  pillar  of  the  fornix  which  fail  to  suffer  synapse 
terminations  within  the  mammillary  body. 

(C)  Efferent  fibers,  the  axons  of  the  pyramidal  cells  of  the  uncus  and 
the  hippocampus  and  the  variously  shaped  cells  of  the  related  dentate 
fascia  of  the  hippocampus,  leave  the  cortical  olfactory  centers  by  way  of 
the  fimbria.     Approximately  twenty-five  per  cent,  of  these  efferent  fibers 
are  continued  into  the  fornix  proper,  for  distribution  to  the  habenular 
ganglion,  the  mammillary  body,  the  brain  stem,  and  points  below.     More- 
over, axons  arising  from  nerve  cell  bodies  within  the  amygdaloid  nucleus 
course  via  the  stria  terminalis  (taenia  semicircularis) ,  opposing  indirection 
the  afferent  components  of  this  stria,  and  enter  the  thalamus,  others  pass 
into  the  internal  capsule  and  to  the  cerebral  cortex  above  (see  page  338). 

The  efferent  fibers  from  the  olfactory  cortex  are  to  be  thought  of  as 
olfactory  associational  and  projection  fibers.  Of  those  that  enter  the  for- 
nix proper,  some  leave  the  latter  and  join  the  stria  medullaris  thalami  (see 
page  337)  for  the  habenular  nuclei  and  the  mid-brain,  others  pass  to  the 
mammillary  body  via  the  corresponding  anterior  pillar  of  the  fornix,  either 
to  terminate  in  this  body  or  to  pass  through  it.1  The  fibers  that  fail  to 
terminate  in  the  mammillary  body  either  cross  to  the  opposite  side  and  be- 
come component  fibers  of  the  tractus  mammillopeduncularis  or  enter  the 
tract  of  Vicq  d'Azyr  (probably  of  both  sides).  It  will  be  recalled  that  the 
former  passes  in  the  reticular  formation  to  the  mid-brain,  pons  and  prob- 
ably to  points  at  lower  levels. 

(D)  Commissural  tracts  connect  the  two  sides  of  the  olfactory  appa- 
ratus.  Approximately  seventy-five  per  cent,  of  the  fibers  which  leave  the 
uncus,  the  hippocampus  and  the  related  dentate  fascia  by  way  of  the  fim- 
bria (see  above)  are  distinctly  smaller  than  the  remaining  association  and 
projection  fibers,  and  are  commissural  in  character.     They  course  in  the 
fimbria,  but  instead  of  being  continued  into  the  fornix  proper  pass  by  way 
of  the  hippocampal  commissure  (transverse  fornix,  lyre,  ventral  psalterium) 
to  the  fimbria  and  hippocampus  of  the  opposite  side,  thereby  connecting 
the  olfactory  cortices  of  the  two  sides.     Moreover,  the  anterior  cerebral 
commissure  contains  a  small  olfactory  fasciculus  which  connects  the  ol- 

1  Despite  the  fact  that  many  fibers  pass  through  the  mammillary  body,  synapse  relations  arc 
established  with  the  cells  in  loco  by  collaterals  from  the  fibers. 


344  THE  OLFACTORY  APPARATUS  PROPER 

factory  bulbs  of  the  two  sides — true  commissural  fibers — and  the  olfactory 
bulb  of  one  side  with  the  uncus  of  the  other  side.  According  to  Van  Ge- 
huchten,1  however,  none  of  the  fibers  of  the  anterior  commissure  arise  from 
the  nerve  cells  located  within  the  olfactory  bulb.  He  believes  that  the 
olfactory  portion  of  the  commissure  is  an  association  system  connecting 
the  olfactory  cortex  of  one  side  with  the  olfactory  bulb  of  the  other. 

The  Relations  of  the  Brain  to  the  Walls  of  the  Nasal  Fossae  and  the 
Paranasal  Sinuses. — But  brief  mention  of  the  anatomic  naso-encephalic 
relations  need  be  made  here  since  reference  to  the  relationships  is  made  in 
the  foregoing  chapters.  This  is  especially  true  for  the  meningeal  relations, 
the  hypophysis  cerebri  and  the  cavernous  sinus. 

The  olfactory  bulb  and  tract  lie  in  very  close  relation  with  the  roof 
of  the  nasal  cavity.  While  the  olfactory  bulb  usually  rests  more  or  less 
freely  upon  the  cranial  surface  of  the  lamina  cribrosa  of  the  ethmoid  bone, 
it  is  at  times  markedly  encroached  upon  by  the  dorsomedial  extension 
of  the  frontal  sinus,  by  a  cell  in  the  crista  galli,  or  by  ethmoidal  cells. 
Frequently  such  encroachments  merely  lead  to  a  crowding  of  the  olfactory 
bulb  in  one  direction  or  another.  When,  however,  these  sinus  and  cell 
extensions  occur  simultaneously  the  olfactory  bulb  may  be  pinched  upon 
to  a  marked  degree  (Fig.  200).  The  author  is  unable  to  say  whether  this 
has  any  bearing  upon  atrophy  of  the  olfactory  bulb  or  upon  the  physiology 
of  smell. 

The  frontal  sinuses  come  into  relationship  with  the  brain  cortex  in 
the  neighborhood  of  the  pole  of  the  frontal  lobe.  It  is  essential  in  this 
connection  to  recall  the  extensive  pneumatizations  of  the  frontal  sinus 
that  are  not  infrequently  encountered  (Figs.  113  and  114).  Naturally, 
the  brain  exposure  is  in  accord  with  the  size  of  the  frontal  sinus. 

The  ethmoidal  cells  lie  opposite  the  gyrus  rectus  and  usually  come  into 
relationship  with  the  basal  cortex  for  a  goodly  distance  lateral  to  the  gyrus 
rectus.  Dorsally  the  sphenoidal  sinus  replaces  the  ethmoidal  cells  in  this 
relationship.  While  the  sphenoidal  sinus  is  usually  separated  laterally 
from  the  brain  cortex  by  the  intervening  cavernous  sinus,  it  occasionally 
pneumatizes  beneath  and  lateral  to  the  cavernous  sinus  and  comes  into 
most  intimate  relationship  with  the  temporal  lobe  of  the  brain  (Fig.  142). 
It  is,  therefore,  possible  for  an  abscess  of  the  temporal  lobe  to  arise  from 
a  diseased  state  of  the  sphenoidal  sinus. 

An  appreciation  and  knowledge  of  the  relations  and  variations  of  the 
paranasal  sinuses  are  alone  of  value  in  the  localization  of  rhinogenic  brain 
abscesses  of  paranasal  origin. 

1  Le  Xevraxe,  1904. 


XII-PHYSIOLOGICAL  ADDENDA 


CHAPTER  XII 

PHYSIOLOGICAL  ADDENDA 

The  Nose  Proper. — The  functions  of  the  nose  proper  are  of  divers 
sorts.  Only  small  portions  of  the  definitive  or  adult  nasal  fossae  are  spe- 
cifically olfactory  in  function  (see  the  peripheral  olfactory  organ,  page  325). 
The  remaining  and  greater  portions  of  the  nasal  fossae  conjointly  serve 
the  role  of  an  adjunct  respiratory  organ  despite  the  fact  that  the  primitive 
or  primary  nasal  fossae  and  their  derivatives  are  wholly  olfactory  in  their 
physiology.  The  respiratory  role  is  purely  secondary  as  is  evidenced  by 
the  embryology  and  comparative  anatomy  of  the  nose  (see  Chapter  I). 
The  nasal  cavity  serves  ancillary  roles  in  connection  with  audition,  taste, 
and  the  proper  production  of  voice;  moreover,  serves  as  a  drainage  cavity 
for  the  paranasal  sinuses  and  the  nasolacrimal  apparatus.  The  nasal 
mucous  membrane  in  its  normal  condition  is  supposed  to  have  certain 
bactericidal  properties,  whereby  the  nasal  fossae  become  defensive  organs 
against  the  invasion  of  bacteria  by  way  of  the  inspired  air.  The  external 
nose  very  frequently  reproduces  to  a  marked  degree  family  and  racial 
characteristics  and  through  the  attachment  of  facial  muscles  modifies 
facial  expression. 

It  is  generally  believed  that  the  current  of  air  in  passing  through  the 
nasal  fossae  does  not  pursue  a  straight  course,  but  passes  in  curves  and 
eddies.  This  leads  to  a  prolonged  stay  of  the  air  within  the  nasal  cavity; 
moreover,  aids  in  the  dissemination  of  the  air  into  the  various  recesses, 
etc.,  of  the  very  irregularly  configured  lateral  nasal  walls.  The  fore- 
going are  important  factors  in  warming  and  moistening  the  air  before 
it  passes  into  the  nasopharynx.  The  great  vascularity  of  the  nasal  mucous 
membrane  and  the  secretions  of  the  nasal  glands  are  the  prime  factors  in 
supplying  heat  and  moisture  to  the  inspired  air.  By  the  time  the  air  has 
reached  the  larynx  it  is  normally  warmed  to  blood  temperature  and  laden 
with  moisture.  The  erectile  tissue  of  the  nose  is  especially  active  and  un- 
dergoes engorgement  when  the  air  is  dry,  thereby  providing  the  neces- 
sary moisture.  When  the  inhaled  air  is  humid  the  erectile  tissue  is  less 
active.  It  has  been  estimated  that  in  twenty-four  hours  over  a  liter  of 
water  is  normally  supplied  by  the  nose  and  that  when  the  functions  of  the 

347 


348  PHYSIOLOGICAL  ADDENDA 

latter  are  impaired  there  is  a  dryness  and  tendency  to  catarrh  in  the  nose, 
pharynx,  trachea,  etc.  (Figs.  159,  181  and  183). 

The  nose  normally  acts  as  a  filter  for  particles  of  dust  and  bacteria 
with  which  the  inhaled  air  is  laden.  The  vibrissae  located  in  the  nasal 
vestibules  entangle  many  of  these  and  keep  them  from  reaching  the  nasal 
mucous  membrane  proper.  The  vestibules  are  always  laden  with  mi- 
croorganisms (mostly  non-pathogenic) ;  fewer  are  found  in  the  nasal  fossae 
and  fewer  still  in  the  nasopharynx.  Dust  particles  and  microorganisms 
which  reach  the  nasal  fossae  and  paranasal  sinuses  are  normally  expelled 
by  the  action  of  the  ciliated  epithelium  and  the  secretion  of  the  nasal 
glands.  The  activity  of  phagocytes  is,  doubtless,  also  a  factor.  The  cur- 
rent produced  by  the  ciliated  epithelium  of  the  nasal  fossae  is  toward  the 
nasopharynx  and  that  of  the  paranasal  sinuses  is  toward  the  ostia  of 
the  sinuses,  therefore,  toward  the  nasal  fossae.  This  was  confirmed  by 
the  author  by  placing  powdered  carbon  on  the  mucous  membranes  of  the 
paranasal  sinuses  in  a  number  of  animals.  The  observation  showed  that 
the  carbon  particles  were  carried  into  the  nasal  fossae  and  from  there  into 
the  nasopharynx. 

While  the  active  bactericidal  property  of  the  secretion  of  the  nasal 
glands  is  questioned  by  some,  it  is  doubtless  established  that  it  has  at 
least  a  marked  inhibitory  influence  on  the  growth  of  microorganisms. 
This  is  equally  true  of  the  paranasal  sinuses.  Thomson  and  Hewlet  found 
when  cultures  of  non-pathogenic  organisms  are  artificially  introduced  into 
the  nose  they  disappear  rapidly.1  This  probably  accounts  for  the  great 
abundance  of  microorganisms  in  the  nasal  vestibules  and  for  their  relative 
scantiness  in  the  interior  of  the  nasal  fossae  and  their  almost  total  disap- 
pearance in  the  upper  portions  of  the  pharynx.  Bertarelli  and  Calamida2 
claim  that  the  paranasal  (accessory)  sinuses,  in  animals  at  least,  are  always 
sterile.  Torne3  found  the  paranasal  sinuses  of  human  bodies  just  dead 
to  be  sterile.  In  a  later  observation4  he,  however,  found  bacteria  present, 
indicating  that  the  inspired  air  carries  microorganisms  into  the  paranasal 
sinuses.  It  is,  however,  definitely  known  that  the  paranasal  sinuses 
are  not  the  conspicuous  habitat  for  microorganisms  as  was  one  time  gen- 
erally believed.  Two  prominent  physiologic  factors  come  into  play  in 
ridding  the  nasal  fossae  and  its  related  paranasal  sinuses  of  bacteria :  first, 
the  action  of  the  ciliated  epithelium  and  second,  the  apparent  bactericidal 
or  surely  inhibitory  properties  of  the  nasal  mucus.  Should  these  defensive 

1  Med.-Chir.  Trans.,  Vol.  78,  1895. 

2  Archivio  Itilano  di  Otologica,  Vol.  13. 

3  Nord.  Med.  Arkiv.,  H.  i,  1904. 

4  Central,  f.  Bakteriologie,  Bd.  33,  1903. 


NASAL  FOSS.E  349 

mechanisms  be  overcome  by  invading  bacteria,  infection  of  the  nose  and 
paranasal  sinuses  is,  of  course,  inevitable.  Phagocytes  and  solitary 
lymph  nodes  of  the  nasal  mucosa  may  be  additional  protective  agencies. 
St.  Clair  Thomson  in  commenting  upon  the  bactericidal  functions  of  the 
secretion  of  the  nasal  glands  emphasizes  the  importance  of  respecting  the 
erectile  tissue  portions  of  the  nasal  mucous  membrane;  arguing  that  "it 
is  better  to  be  a  partial  mouth-breather  than  to  have  free  nasal  passages 
with  their  protective  mechanisms  seriously  damaged." 

The  nasal  cavities  exert  a  profound  influence  upon  vocalization.  The 
sound- vibrations  which  arise  in  the  larynx  and  ascend  in  the  pharynx 
require  a  resonating  chamber  for  the  realization  of  a  full  and  clear  sonorous 
tone  of  the  human  voice;  for  some  sounds  this  chamber  is  found  in  the 
ever  open  nasopharynx  and  the  nasal  fossae  with  their  posterior  and  an- 
terior apertures.  If  the  nasal  fossae  or  their  apertures  are  blocked  by  patho- 
logic conditions,  marked  changes  in  some  of  the  fundamental  sounds  are 
encountered.  The  soft  palate  likewise  is  of  importance  in  this  connec- 
tion— its  movements  must  be  free  and  unimpeded.  The  voice  of  every 
individual  has  a  peculiar  quality,  clang  or  timber.  This  is  dependent 
upon  the  shape,  size  and  health  of  the  cavities  connected  with  the  larynx. 
In  nasal  tones  the  air  in  the  nasal  fossae  vibrates  freely,  necessitating,  there- 
fore, free  nasal  fossae  and  apertures.  The  nasal  timber  is  produced  by  the 
soft  palate  (palatum  molle)  not  shutting  off  completely  the  nasal  fossae, 
happening  when  pure  vowels  are  sounded  with  a  resultant  sympathetic 
vibration  of  the  air  in  the  nasal  fossae.  It  has  been  shown  that  "when  a 
vowel  is  spoken  with  a  nasal  timber,  air  passes  out  of  the  nose  and  mouth 
simultaneously,  while  with  a  pure  vowrel  sound,  it  passes  out  only  through 
the  mouth."  Hartmann  has  demonstrated  that  it  requires  an  artificial 
pressure  of  30  to  100  mm.  of  mercury  to  overcome  the  soft  palate  when 
sounding  a  pure  or  non-nasal  vowel,  so  complete  is  the  physiologic  occlu- 
sion between  the  oropharynx  and  the  nasopharynx.  The  vowels,  a,  a  (ae),  6 
(ce),  o,  e,  are  used  with  a  nasal  timber.  Strictly  speaking  a  nasal  i  does 
not  occur  in  any  language  since  it  is  next  impossible  to  sound  it  as  such 
under  normal  conditions,  since  the  bulk  of  the  air  passes  out  through  the 
nasal  fossae  and  their  apertures.  According  to  their  mechanism  of  forma- 
tion consonants  may  be  divided  into  explosives,  vibratives,  aspirates,  and 
resonants.  In  the  sounding  of  the  latter  group  the  nasal  fossae  are  en- 
tirely free,  while  the  oral  aperture  is  shut  off;  therefore,  they  are  frequently 
called  nasals  or  semi- vowels.  In  the  former  three  groups  the  nasal  cavity 
is  entirely  shut  off. 

The  foregoing  will  suffice  to  show  the  importance  of  healthy  and  nor- 


350  PHYSIOLOGICAL  ADDENDA 

mal  nasal  fossae  in  vocalization.  The  reader  is  referred  to  the  special 
treatises  on  voice  and  sounds  for  more  detailed  discussions.  It  would  lead 
us  too  far  afield  to  undertake  it  here. 

The  Paranasal  Sinuses. — Various  functions  have  been  ascribed 
the  paranasal  sinuses,  some  of  which  are  unwarranted,  others  purely 
hypothetical,  while  a  third  group  are  suggestive  and  within  the  field  of 
probability.  It  is  not  profitable,  however,  in  this  connection  to  speak 
of  the  many  theories  that  have  been  advanced,  suffice  it  to  speak  of  those 
that  appear  tenable. 

The  author  is  of  the  firm  opinion  that  until  the  phylogenic  beginning 
of  the  paranasal  (accessory)  sinuses  is  more  definitely  established  the 
functions  of  the  cavities  must  necessarily  remain  more  or  less  obscure. 
Indeed,  the  initial  functions  of  the  sinuses  may  have  been  entirely  replaced 
by  secondary  functions  in  man.  Comparative  anatomy  has,  of  course, 
given  some  light  and  further  study  in  this  direction  is  essential.  It  is  not 
an  easy  task  to  map  out  accurately  the  olfactory  field  in  a  large  series  of 
mammals.  The  embryology  or  ontogenetic  history  of  the  paranasal 
sinuses  is  well  known  for  a  number  of  forms  (see  Chapter  I  for  man), 
but  what  is  especially  wanted  now  is  the  phylogenetic  history. 

It  would  appear  certain  that  the  paranasal  sinuses  are  old  in  their 
phylogeny  since  they  begin  their  ontogenetic  development  relatively  early 
in  the  human  embryo  (see  pages  36  to  37).  This  belief  is  supported  by 
the  recent  observations  of  Moodie1  who  had  the  opportunity  of  studying 
the  casts  of  the  paranasal  sinuses  of  two  early  tertiary  mammals — oreo- 
dont2  (Merycochoerus)  and  an  early  bear-dog  (Daphaenus).  The  casts 
made  by  nature  and  preserved  in  fossil  form  indicated  an  enormous  de- 
velopment of  the  frontal  and  maxillary  sinuses.  A  study  of  the  casts 
leads  Moodie  to  believe  that  the  origin  of  the  paranasal  chambers  "is  to 
be  found,  not  in  the  early  mammals,  but  in  their  ancestors,  and  probably 
their  remote  ancestors."  Descriptive  paleontology  may  indeed  prove  a 
valuable  supplement  to  comparative  embryology,  anatomy  and  physiology 
in  an  effort  to  solve  the  real  meaning  of  the  paranasal  sinuses,  both  primi- 
tive and  recent. 

Smell  is  evidently  the  dominant  sense  in  very  many  of  the  lower 
vertebrates.  This  is  evidenced  by  the  great  development  of  the  olfactory 
brain  and  the  behavior  of  such  animals.  In  man  and  other  primates  the 
olfactory  organ  is  much  reduced  and  the  olfactory  sense  relatively  very 
rudimentary  (see  page  328).  As  stated  elsewhere,  in  accordance  with  the 

1  On  the  Sinus  Paranasales  of  Two  Early  Tertiary  Mammals,  Jour.  Morph.,  Vol.  28,  1916. 
2Leidy  speaks  of  the  genera  of  the  Oreodontidae  as  "ruminating  hogs." 


PARANASAL  SINUSES  351 

degree  of  development  of  the  olfactory  apparatus,  one  may  distinguish 
between  mammals  which  are  macrosmatic  (most  of  the  mammalian  orders), 
microsmatic  (seals,  whalebone-whales,  and  primates,  including  man), 
and  anosmatic  (most  toothed- whales).  In  Mammalia,  except  in  Mono- 
tremata,  the  nasal  fossae  communicate  with  one  or  more  paranasal  cham- 
bers; e.g.,  the  maxillary,  frontal,  and  sphenoidal  sinuses  (the  three  sinuses 
are  not  necessarily  present  in  all  forms).  In  some  forms  that  have  been 
carefully  studied  olfactory  folds  are  enclosed  in  the  paranasal  sinuses  men- 
tioned, especially  the  frontal  and  sphenoidal.  With  the  reduction  of  the 
olfactory  sense  in  other  forms  there  is  a  resultant  loss  of  the  primary  olfac- 
tory function  of  the  sinuses — a  pneumatic  and  purely  secondary  role 
being  assumed.  Indeed,  the  sinuses  may  disappear  altogether;  witness, 
for  example,  Pinnipedia  (seals,  walruses).  The  maxillary  is  the  most 
constant  of  the  sinuses,  being  typical  for  Eutheria,  and  the  only  sinus 
present  in  Insectivora  and  bats. 

The  author  is  of  the  opinion  that  the  paranasal  sinuses  of  man  no 
longer  fill  the  role  initially  set  for  them  in  their  phylogenetic  history. 
There  is  considerable  evidence  that  the  olfactory  mucous  membrane  was 
much  more  extensive  at  one  time.  Indeed,  as  indicated  above,  it  is 
more  extensive  in  many  of  the  lower  mammals.  The  fact  that  the 
entire  embryonic  nasal  fossae  of  man  (see  page  47)  are  initially  olfac- 
tory in  their  character,  e.g.,  in  their  embryonic  development,  would  seem 
to  indicate  that  phylogenetically  the  olfactory  nasal  mucosa  was  more 
extensive  than  it  is  in  the  post-embryonic  human  nose.  The  respiratory 
role  of  the  human  nasal  cavity  is  clearly  secondary.  In  all  likelihood, 
therefore,  in  the  phylogeny  of  the  human  nose,  the  olfactory  mucosa  pri- 
marily extended  into  the  derivatives  of  the  nasal  fossae,  e.g.,  certain  of  the 
paranasal  sinuses;  this  in  order  that  the  area  of  the  olfactroy  mucosa 
be  increased  and  a  correspondingly  more  acute  sense  of  smell  provided. 
Man  and  the  anthropoids  not  requiring  the  strong  sense  of  smell  for  their 
existence  and  survival  became  macrosmatic  (possessing  smell  in  a  com- 
paratively feeble  degree) ;  the  respiratory  field  of  the  nasal  mucous  mem- 
brane gradually  encroaching  upon  the  olfactory  field  and  reducing  it  to 
the  limited  area  in  the  upper  portion  of  the  nasal  fossa;  moreover,  the 
olfactory  elements  becoming  completely  lost  to  the  paranasal  sinuses. 

Strictly  speaking,  the  olfactory  nature  of  the  ethmoid  cells  cannot 
be  argued  since  the  ethmoid  labyrinth  is  not  present  as  such  in  most 
macrosmatic  or  acutely  smelling  animals.  In  these  forms  the  ethmoid 
field  assumes  a  great  complexity  and  maze  of  endo-  and  ectoturbinals, 
enclosing  within  their  scroll-like  folds  portions  of  the  nasal  fossa.  These 


352  PHYSIOLOGICAL  ADDENDA 

fossa-inclusions  can,  however,  not  be  spoken  of  as  "ethmoid  cells," 
since  the  latter  designation  connotes  an  entirely  erroneous  conception  of 
these  structures  both  as  to  their  genesis  and  real  anatomy.  The  ethmoid 
labyrinth,  composed  of  sinuses  or  cells  not  unlike  the  frontal,  maxillary 
and  sphenoidal  sinuses,  reaches  its  perfection  as  such  in  some  of  the  an- 
thropoids and  man.  Despite  the  phylogenetically  late  appearance  of  true 
ethmoidal  cells,  the  ethmoidal  labyrinth  as  found  in  man  simulates  in  a 
measure  the  very  complex  field  of  ecto-  and  endoturbinals  with  nasal- 
cavity  inclusions  of  acutely  smelling  or  macrosmatic  animals.  The  scroll- 
like  inclusions  of  the  turbinal  field  of  macrosmatics  are  in  a  sense  analogous 
to  the  cells  of  the  ethmoidal  labyrinth  of  man  and  certain  anthropoids. 
However,  it  must  be  strictly  understood  that  they  are  not  morphologically 
homologous.  The  great  reduction  of  the  ethmoidal  field  in  man  naturally 
precludes  the  formation  of  inclusions  of  the  nasal  fossa  save  to  a  limited 
extent  (see  the  furrows  of  the  middle  meatus,  pages  28-35).  The  direct 
outgrowth  of  the  nasal  mucosa  in  the  formation  of  the  ethmoidal  cells  and 
the  pneumatizaton  of  the  ethmoid  and  neighboring  bones  is  the  nearest 
approach  to  the  complicated  scroll-like  formations  of  macrosmatic  animals. 

Since  smell  is  a  chemically  excited  sense  requiring  a  solution  of  the 
gaseous  odoriferous  substances  in  the  moisture  of  the  olfactory  mucous 
membrane  before  the  olfactory  receptors  are  stimulated,  it  was  obviously 
necessary  from  the  phylogenetic  beginning  of  the  paranasal  chambers 
that  air  passes  into  them  in  order  that  the  olfactory  elements  might  be 
stimulated.  It  is,  therefore,  clear  that,  while  the  olfactory  function  of  the 
sinuses  may  have  been  primary,  the  role  as  pneumatic  cavities  and  adjuncts 
to  respiration  was  perforce  equally  primitive. 

With  the  withdrawal  of  the  olfactory  functions  in  the  phylogenetic 
development  of  the  sinuses  in  man,  the  one  conspicuous  and  probably 
dominant  function  remaining  is  that  as  an  adjunct  to  respiration,  parti- 
cularly to  aid  in  humidifying  and  warming  the  inspired  air.  It  has  been 
definitely  established,  especially  by  Braune  and  Clasen,  that  during 
respiration  there  is  a  certain  amount  of  air  change  in  the  paranasal  sinuses. 
The  degree  of  interchange  of  air  is  obviously  more  or  less  dependent  upon 
the  size  and  freedom  of  the  ostia  of  the  respective  sinuses  and  the  amount 
of  air  inspired.  Good  ventilation  of  the  paranasal  sinuses  is  essential  to 
health  and  is  normally  maintained.  Pathologic  states  in  the  nasal  fossae 
may  seriously  block  the  interchange  of  air  by  encroachment  on  the  ostia 
of  communication  between  the  sinuses  and  the  nasal  fossae. 

A  number  of  investigators  support  the  theory  that  in  order  to 
have  proper  equipoise  of  the  head  it  is  necessary  that  seme  of 


PARAXASAL  SINUSES  353 

its  bones  be  pneumatized.  Such  pneumatization  is  found  in  the 
paranasal  sinuses  and  from  this  is  inferred  that  the  main  function 
of  the  sinuses  is  to  lighten  the  bones  of  the  skull.  Braune  and 
Clasen1  particularly  have  opposed  such  function  in  view  of  the  fact 
that,  according  to  their  studies,  but  one  per  cent,  would  be  added  to  the 
weight  of  the  skull  should  the  pneumatic  cavities  be  replaced  by  spongy 
bone.  Their  contention  would  merit  more  support  if  the  pneumatization 
of  the  head  bones  should  be  equally  distributed.  It,  however,  happens  that 
practically  the  entire  system  of  pneumatic  cavities  is  located  in  the  ventral 
portion  of  the  head.  It  appears  plausible,  therefore,  should  the  paranasal 
sinuses  be  replaced  by  solid  bone,  that  the  poise  and  equipoise  of  the  head 
would  be  markedly  interfered  with,  since  the  head  with  the  contained 
sinuses  is  very  evenly  balanced.  The  argument,  that  the  theory  of  light- 
ness and  balance  of  the  skull  as  related  to  the  paranasal  sinuses  fails  be- 
cause children  have  no  sinuses  yet  are  able  to  balance  their  heads,  is  not 
permissible,  since  children  do  have  fairly  well  developed  sinuses  even  at 
birth. 

It  is  very  unlikely  that  the  paranasal  sinuses  exert  any  influence  upon 
vocalization.  The  ostia  of  the  sinuses  are  so  small  and  not  infrequently 
encroached  upon  by  neighboring  parts  that  one  naturally  wonders  how  the 
chambers  can  have  any  modifying  influence  on  the  sound  waves.  More- 
over, the  great  variations  in  the  size  and  arrangement  of  the  sinuses  would 
preclude  any  constancy  of  influence.  The  theory  that  the  paranasal  sin- 
uses impart  resonance  to  the  voice  must,  doubtless,  be  abandoned 

In  view  of  the  fact  that  the  mucous  membranes  of  the  paranasal  sin- 
uses are  very  sparsely  supplied  with  glands,  the  theory  that  the  dominant 
function  of  the  sinuses  is  to  supply  moisture  in  the  form  of  mucus  to  the 
nasal  fossae  is  archaic  and  unwarranted,  since  a  very  limited  amount  of 
moisture  is  thus  supplied. 

Under  normal  conditions  the  paranasal  sinuses  are  capable  of  self-drain- 
age. All  of  them  are  lined  by  a  ciliated  epithelium,  with  a  wave-like  ciliary 
motion  directed  toward  the  ostia  of  the  sinuses.  It  must,  however,  be 
recalled  that  in  the  human  nose  the  maxillary  and  sphenoidal  sinuses  and 
certain  of  the  ethmoidal  and  conchal  cells  have  no  gravity  drainage.  Most 
of  the  ethmoidal  cells  and  the  frontal  sinuses  have  their  ostia  so  located  that 
gravity  itself  is  a  material  factor  in  freeing  the  sinuses  of  accumulated 
mucus.  Of  course,  when  the  position  of  the  body  is  changed  from  the 
erect  posture  to  the  horizontal,  or  better  when  the  head  is  placed  with  its 
vertex  downward,  the  maxillary,  sphenoidal  and  conchal  cells  likewise 

1  Zeit.  f.  Anat.,  Bd.  2,  1877. 
23 


354  PHYSIOLOGICAL  ADDENDA 

have  a  gravity  drain.  This  discrepancy  in  the  location  and  relations  of 
the  ostia  of  the  several  sinuses  accounts  for  the  dissimilarity  of  the  sub- 
jective symptoms  (other  things  being  equal)  in  diseased  states  of  the  indi- 
vidual sinuses. 

Olfactory  Sensation. — The  development  and  complexity  of  the  ol- 
factory lobes  of  the  cerebrum  and  the  nasal  fossae  in  mammals  vary  greatly 
and  are  in  accord  with  the  degree  of  acuity  of  the  sense  of  smell.  Of 
course,  the  immediate  intensity  of  the  olfactory  sensation  depends  on  the 
size  of  the  olfactory  fields  in  the  nasal  fossae,  the  concentration  of  the  odor- 
iferous substance  and  the  frequency  of  the  conduction  of  the  substance 
by  sniffing  to  the  olfactory  receptors.  Certain  animals  have  no  sense  of 
smell  (anosmatic)  including  certain  cetaceous  mammals  like  the  porpoise 
and  toothed  whale,  the  olfactory  nerve  being  absent.  Rarely  there  is 
congenital  anosmia  in  man.  In  other  mammals  the  sense  of  smell  is 
remarkably  acute  (macrosmatic) ,  including  rodents,  carnivora,  marsupials 
and  other  mammals.  Moreover,  there  is  an  intermediate  group  of  animals 
which  possess  smell  in  a  comparatively  feeble  degree  (microsmatic) , 
including  most  primates,  monotremes,  some  cetacea  and  man.  Since  the 
olfactory  function  warns  the  individual  of  offending  gases,  the  olfactory 
organ  assumes  the  additional  role  of  a  protective  organ. 

In  spite  of  the  fact  that  man  is  microsmatic  his  sense  of  smell  is  nor- 
mally aroused  by  inconceivably  dilute  solutions  of  odoriferous  substances — 
one  part  of  mercaptan  to  thirty  billions  of  air  being  detectible.  Valentin 

reports  that  of  a  grain  of  musk  can  be  distinctly  smelled.    Cam- 

100,000,000 

phor  is  perceived  in  a  dilution  of  i  part  to  400,000.  It  is  known  that  the 
acuteness  of  the  sense  of  smell  can  be  greatly  improved  by  practice. 
The  case  of  James  Mitchell,  who  though  deaf ,  dumb  and  blind,  distinguished 
persons  and  objects  by  his  acutely  trained  sense  of  smell,  is  often  re- 
ferred to  in  this  connection.  The  delicacy  of  the  sense  of  smell  varies 
normally  in  different  individuals.  The  threshold  of  excitation  is  much 
lower  for  smell  than  it  is  for  taste  owing  to  the  suppression  of  a  synapse 
in  the  peripheral  olfactory  receptors  in  the  nasal  mucosa  and  to  peculiari- 
ties in  the  neuron  synapses  in  the  olfactory  bulb  (page  338).  The  olfac- 
tory organ  responds  to  a  much  larger  range  of  chemical  stimuli  and  to 
greater  dilutions  than  does  the  gustatory  organ.  Parker  and  Stabler1 
have  shown  that  the  human  olfactory  organ  responds  to  alcohol  at  a  dilu- 
tion 24,000  times  greater  than  that  necessary  to  activate  the  organ  of 

1  On  Certain  Distinctions  between  Taste  and  Smell,  Amer.  Jour.  Physiol..  Vol.  XXII,  pp.  230  to 
240. 


OLFACTORY  SENSATION  355 

taste.  The  interrelations  between  taste  and  smell  are,  however,  very 
important  (vide  infra).  Strangely  the  olfactory  receptors  are  almost  as 
readily  fatigued  as  they  are  excited  and  the  sense  of  smell  soon  becomes 
untrustworthy  as  an  organ  for  the  detection  of  odoriferous  substances. 
Many  inhaled  substances  after  a  brief  period  cease  to  produce  a  detectible 
sensation.  The  normal  individual  readily  notices  the  unpleasant  odor 
upon  entering  an  ill- ventilated  room,  yet  after  the  lapse  of  a  few  minutes 
ceases  to  perceive  it  because  of  the  fatigue  of  his  olfactory  apparatus. 
A  completely  fatigued  apparatus  recovers,  however,  in  a  very  short  time, 
provided  the  environment  is  suitable. 

It  would  appear  established  that  smell  in  man,  as  probably  in  all 
present  vertebrates,  has  both  exteroceptive  and  interoceptive  qualities. 
Despite  the  fact  that  primitively  smell  was  an  interoceptive  sense  it  is 
now  dominated  by  the  exteroceptive  quality.  However,  some  of  its 
initial  quality  persists.  As  Herrick  states,  the  somatic  reactions  are 
obviously  more  important  than  the  visceral  responses. 

Smell  like  taste  is  a  chemically  excited  sense.  It  requires  a  solution 
of  the  gaseous  odoriferous  substances  in  the  moisture  of  the  olfactory 
mucous  membrane  before  the  olfactory  receptors  are  stimulated.  The 
mucous  membrane  must  be  neither  too  moist  nor  too  dry  for  the  most 
favorable  reaction.  Strangely  all  gaseous  substances  do  not  stimulate 
the  olfactory  receptors,  and  it  is  assumed  according  to  Howell  and  others 
that  there  are  certain  odoriphore  groups  which  are  characteristic  of  all 
odoriferous  substances  and  by  virtue  of  which  these  substances  react  with 
the  special  form  of  protoplasm  found  in  the  olfactory  hair  cells.  Halli- 
burton says  that  generally  the  odors  of  homologous  series  of  compounds 
increase  in  intensity  with  increase  of  molecular  weight,  but  bodies  of  very 
low  molecular  weight  are  odorless,  while  vapors  of  very  high  molecular 
weight,  which  escape  and  diffuse  slowly,  have  little  or  no  smell. 

The  passage  of  odoriferous  substances  to  the  olfactory  receptors 
is  accomplished  by  mere  diffusion  or  by  the  act  of  sniffing  which  produces 
currents  of  air  and  intensifies  the  sensation.  The  peripheral  localization 
is  very  imperfect  since  individuals  confound  many  smells  with  tastes. 
Many  flavors  (tastes)  are  really  smells,  the  odoriferous  substances  which 
are  being  eaten  in  all  probability  reaching  the  peripheral  olfactory  organ 
through  the  choanae,  and  since  they  accompany  the  presence  of  food  or 
other  particles  in  the  mouth  are  interpreted  as  gustatory  sensations  rather 
than  olfactory.  Indeed,  it  is  well  known  to  everyone  that  blocking  of 
the  choanae  (posterior  nares)  by  a  nasopharyngeal  pathology  and  the  nares 
and  nasal  fossae  by  a  coryza  loses  much  flavor  value  of  foods  to  the  in- 


356  PHYSIOLOGICAL  ADDENDA 

dividual.  Physicians  and  mothers  well  know  that  compressing  the  nares 
(nostrils)  of  the  little  rebellious  patient  makes  easier  the  administration 
of  certain  drugs  by  mouth — much  of  the  so-called  "  taste"  of  the  medicine 
is  destroyed  thereby. 

Many  attempts  have  been  made  to  discover  the  fundamental  or 
elementary  sensations  of  smell  as  has  been  satisfactorily  done  for  taste 
(sour,  salty,  sweet,  bitter).  Ordinarily  individuals  are  content  to  speak 
of  olfactory  sensations  as  agreeable  or  pleasant  and  disagreeable  or  repul- 
sive. In  addition  to  these  Haller  suggested  a  third — the  mixed.  It 
is  held  by  some  that  the  agreeable  or  disagreeableness  of  the  olfactory  sen- 
sations (odors  or  smells)  is  in  many  instances  dependent  upon  the  olfactory 
associations  connected  with  them,  i.e.,  if  the  associative  memories  aroused 
are  unpleasant  the  odor  is  repulsive  or  disagreeable  and  vice  versa.  One 
of  the  most  complete  classifications  of  odors  is  given  by  Zwarrdemaker.1 
He  classifies  them  into  (i)  pure  odors,  (2)  odors  confused  with  taste  and  (3) 
odors  mixed  with  common  sensibility  of  the  mucous  membrane  of  the 
nose.  These  primary  groups  are  subdivided  into  secondary  groups.  It 
is  well  known,  for  example,  that  ammonia  a  pungent  substance,  stimulates 
the  endings  of  the  trigeminal  nerve  as  well  as  those  of  the  olfactory  nerve. 
The  so-called  taste  of  spices  is  not  perceived  when  the  nose  is  compressed 
and  the  nares  closed  oft,  a  certain  pungency  alone  being  experienced, 
due  to  a  stimulation  of  the  nerves  of  general  sensation.  If,  however, 
the  nose  is  freely  open  "taste"  is  experienced  which  is  in  reality  smell. 

When  two  odoriferous  substances  are  simultaneously  inhaled,  one 
may  be  dominant  and  the  other  secondary  or  entirely  suppressed  in  the 
consciousness.  On  the  other  hand,  one  of  the  odors  may  be  perceived  and 
after  a  very  brief  pause  the  other,  or  the  two  odors  may  be  perceived  as  a 
mixed  odor  and  be  unlike  either  of  the  elementary  odors.  Some  odorifer- 
ous substances  readily  fatigue  the  olfactory  receptors  in  the  nasal  mucosa. 
However,  the  receptors  may  be  fatigued  by  one  substance,  yet  be  acutely 
sensitive  and  active  to  others.  This  leads  one  to  think  of  either  a  selective 
power  of  the  units  composing  the  peripheral  olfactory  organ  or  that  some 
substances  affect  some  portion  of  the  olfactory  mucosa,  while  others  affect 
other  parts.  It  is,  of  course,  well  known  that  the  organ  is  variously  sensi- 
tive to  different  odoriferous  substances. 

As  stated  elsewhere  the  cortical  olfactory  center  located  in  the  hippo- 
campus and  the  uncus  is  widely  connected  with  other  parts  of  the  cerebrum. 
These  connections  serve  as  an  anatomic  basis  for  the  extensive  association 
connected  with  the  odors.  Olfactory  sensations  often  awaken  powerful 

1  Die  Physiologic  des  Geruchs,  Leipsig,  1895. 


INHERITANCE  AND  SMELL  357 

multitudinous  associations  of  memory  and  as  Howell1  aptly  says,  "our 
olfactory  memories  are  good." 

It  has  long  been  observed  that  obvious  important  relationships 
exist  between  the  olfactory  and  the  sexual  organs.  In  animals  with  highly 
developed  olfactory  organs,  both  vertebrate  and  invertebrate,  the  olfactory 
sense  is  intimately  connected  with  the  sexual  reflexes  (see  also  page  296). 
Moreover,  a  remnant  of  such  relationships  is  very  apparent  among  human 
beings.  Howell2  rightly  states  that  "among  the  so-called  special  senses 
that  of  smell  is  the  one  most  closely  connected  with  the  bodily  appetites, 
and  over-gratification  or  over-indulgence  of  this  sense,  according  to  histor- 
ical evidence,  has  at  least  been  associated  with  periods  of  marked  de- 
cadence of  virtue  among  civilized  nations." 

There  exists  also  apparently  a  physiologic  and  pathologic  relationship 
between  the  non-olfactory  nasal  mucosa  and  the  sexual  organs.  It  is 
said  that  inflammations  of  the  nasal  fossae  and  the  paranasal  sinuses  ex- 
ercise a  marked  influence  over  the  sexual  functions.  (See  Chapter  X 
for  a  fuller  discussion.)  The  author  recently  learned  of  a  few  individuals 
in  whom  during  every  sexual  excitement  the  glands  of  the  nasal  mucous 
membrane  pour  forth  a  voluminous  amount  of  mucous  which  subsides  at 
once  with  the  completion  of  the  sexual  act.  This  is,  of  course,  a  psychic 
condition,  supporting  the  thesis  that  there  is  a  cortical  center  which  acts 
on  the  glandulosecretory  and  vasodilator  centers  (see  page  293). 

Little  is  known  on  the  heritability  of  differences  in  the  sense  of  smell. 
Blakeslee3  has  shown  that  two  individuals  may  exhibit  marked  degrees 
of  sensitivity  to  the  fragrance  of  verbena  flowers.  He  found  in  tests  that 
one  individual  not  infrequently  would  declare  one  of  two  blossoms  emit- 
ting a  fragrant  odor  and  the  other  not,  while  a  second  individual  on  judging 
of  the  same  blossoms  would  declare  the  exact  opposites  as  regards  the 
fragrance  of  the  blossoms.  Glaser4  recently  observed  an  individual, 
A,  who  was  quite  unable  to  distinguish  odors  in  the  usual  way  and  whose 
history  showed  among  his  immediate  sibs  two  sisters  normal  as  regards 
olfaction,  one  brother  the  exact  counterpart  of  A,  and  another  with  but 
slight  capacity  for  the  detection  of  odors.  The  mother  of  A  was  unable 
to  detect  odors  and  her  father  was  similarly  deficient.  A  careful  study 
indicated  that  there  were  certain  resemblances  to  sex-linked  inheritance. 
The  fact  that  the  trait  has  appeared  in  one  collateral  (A's  cousin  is  defec- 
tive in  the  sense  of  smell  and  is  the  daughter  of  a  paternal  aunt  who  is 

1  Textbook  of  Physiology.  Philadelphia,  1914. 
-Loc.  cit. 

3  Science,  N.  S.,  Vol.  48,  1918. 

4  Science,  N.  S.,  Vol.  48,  1918. 


358  PHYSIOLOGICAL  ADDENDA 

anosmatic)  and  two  direct  generations,  is  believed  by  Glaser  to  be  suf- 
ficiently frequent  to  warrant  the  assumption  that  anosmia  is  heritable. 
Moreover,  he  believes  that  anosmia  is  probably  to  be  placed  in  the  list 
of  sex-linked  characters  since  two  sisters  of  A  are  reported  to  be  normal 
as  regards  olfaction. 

It  is  reasonably  certain  that  defects  in  the  sense  of  smell  are  inherited 
in  human  beings,  especially  so  since  the  function  of  olfaction  is  degenerate 
and  vestigial  as  compared  with  other  forms.  Not  infrequently  there  is 
a  striking  difference  in  the  sense  of  smell  on  the  two  sides  of  the  same  in- 
dividual. Again,  the  function  may  be  entirely  suppressed.  While 
anosmia  is,  doubtless,  inherited  at  times,  one  must  ever  be  cautious  not  to 
confuse  anosmia  due  to  diseased  states  of  the  olfactory  mucosa,  the  ol- 
factory bulb  and  tract  or  of  the  olfactory  cortex  with  a  truly  congenital 
anosmia.  Careful  examination  of  the  nasal  fossae  by  a  trained  rhinolo- 
gist,  including  both  macroscopic  and  microscopic  studies,  is  essential 
in  anosmatics.  In  many  instances  such  study  will  place  previously 
believed  congenital  anosmatics  on  the  side  of  the  acquired  type  and  the 
result  of  nasal  disease. 

Strangely  the  condition  of  anosmia  seems  to  be  inbred  in  some  locali- 
ties which  suggests  that  certain  nasal  disorders  are  especially  prevalent, 
leading  to  diseased  olfactory  mucosae  with  a  resultant  suspension  of  smell. 
The  author  doubts  that  anosmia  is  sex-linked  in  inheritance  since  it  occurs 
in  both  women  and  men.  It  would,  however,  seem  that  congenital 
anosmia  is  more  frequently  encountered  in  males.  The  reason  for  this 
is  unknown.  However,  until  the  records  of  a  large  series  of  cases  show  a 
decided  advantage  in  favor  of  men,  it  is  unwise  to  assume  that  anosmia 
is  sex-linked  in  inheritance. 

Functional  anosmia  is  occasionally  encountered.  Wheeler  in  the 
Bulletin  of  the  Canadian  Army  Medical  Corps,  records  an  interesting 
case  of  complete  functional  loss  of  smell  in  a  soldier  who  was  buried  by  an 
explosive  shell,  April,  1917.  The  soldier  recovered  with  the  gustatory 
sense  normal  for  the  four  primary  tastes.  He  was  incapable,  however, 
of  recognizing  his  food,  having  lost  that  fine  discrimination  with  which 
taste  and  not  smell  has  usually  but  erroneously  been  credited.  Following 
electrical  treatments  the  olfactory  function  returned  and  the  patient  was 
again  able  to  recognize  odors.  His  foods  once  more  "tasted"  normal 
and  appetizing. 


INDEX 


Abducens  nerve,  179,  193,  194,  195,  196,  201 
relations  of, 

to  cavernous  sinus,  194 
to  internal  carotid  artery,  194 
to  sphenoidal  sinus,  195 
Aberrant  posterior  ethmoidal  cells,  119,  120 
Accessory  nasal  conchae,  27,  28,  35,  96 
furrows,  30 

bullar  furrow,  30 
infrabullar  furrow,  30 
infundibulum  ethmoidale,  30 
suprabullar  recess,  30 
meatuses,  27,28 
sinuses  (paranasal  sinuses) 

ostium  of  the  maxillary  sinus,  92,  130,  131, 

132,  i33 

rudiments  of,  36 
Afferent  neurons,  291 

sympathetic  neurons,  289,  290 
Agenesis  of  frontal  sinus,  146,  157,  158,  159,  160, 

170 

of  sphenoidal  sinus,  198 
Agger  cells,  97,  141 

nasi,  18,  26,  34,  87,  97,  207        , 

development  of,  18 
Alae  nasi,  68 

Alar  cartilages,  greater,  68 
crura  of,  69 
development  of,  40 
lesser,  70 

Alveolar  processes,  55 
Amydaloid  nucleus,  338 
Anatomical  relations,  nerve  of  pterygoid  canal, 

320,  321 

Anosmia,  354,  358 
Antagonistic  reflexes,  292 
Anterior  cerebral  commissure,  343,  344 

ethmoidal  cells,  34,  35,  141.  151,  152,  153,  *54, 
155,  162,  163,  164,  165,  166,  167,  170, 
171,  172,  207,  212,  214,  215,  216,  217, 
218,  233 

bullar  group  of,  218 
communication  of,  216 
extension  into  the  frontal  sinus,  212 
into  the  middle  nasal  concha,  212 
frontal  group  of,  216 
infundibular  group  of,  216,  217 


Anterior  ethmoidal  nerve,  313 

nares  (see  Nares)  7,  10,  n,  63,  71,  72,  89 

nasal  spine,  66 

palatine  canal,  76 
foramen,  76,  276 
nerve,  310 

perforated  substance,  331 

superior  alveolar  ramus,  311 

dental  nerve,  311 
Antrum    of    Highmore    (see   Maxillary   sinus), 

101-135 

Apertura  pyriformis,  66 
Apex  nasi,  63 

Arcus  superciliaris,  146,  169 
Area  parolfactoria,  329,  331,  333 
Artery  or  arteries 

angularis,  278 

dorsalis  nasi,  278 

ethmoidalis  anterior,  277,  278 
posterior,  278 

external  maxillary  (facial),  275 

infraorbital,  278 

internal  carotid,  275 
maxillary,  275 

labialis  superior,  278 

nasalis  posterior  lateralis,  275 
septi,  276 

nasopalatine,  276 

ophthalmic,  275,  277 

palatina  descendens,  278 

pharyngeal,  278 

sphenopalatine,  275,  276 
Ascending  palatine  artery,  182 
Asymmetry  of  the  nasal  septum,  83,  171 
Atresia  of  the  choanae,  10,  74 
Atrium  meatus  medii,  88,  97 

nasi,  88 
Auditive  tube,  201 

pharyngeal  ostium  of,  202 
Auriculotemporal  nerve,  303 


Basal  cells  (nasal  mucous  membrane),  267 

process  of  the  occipital  bone,  189 
Blood  vessels  of  the  nose  and  paranasal  sinuses, 

275, 276, 277, 278, 279 
Bones  of  the  external  nose,  63 
Bowman's  glands  (see  Olfactory  glands),  268 


359 


3(50 


IXDKX 


Broca,  diagonal  band  of,  333 

parolfactory  area  of,  331,  333,  337,  339 
Buccal  cavity.  55 
Bucconasa)  membranes  (Hochstetter),  9,  10 

rupture  of,  10,  48 
Bulbar  sympathetic  system,  295 
Bulbous  olfactorius,  330 

Bulla  ethmoidalis,  29,  31,  32,  33,  94,  127,128, 
129,  140,  152,  165,  172,  208 

frontalis,  152,  153,  154,  212,  218 
Bullar  cells,  208 

folds,  20,  30,  31,  32,  33,  34 
inferior,  32 
superior,  30,  32 

furrows,  31,  208 

group  of  anterior  ethmoidal  cells,  218 


Canal  of  Stenson,  76 
Canalis  incisivus,  76 
nasolacrimalis,  244 
pharyngeus,  278 
Canine  fossa,  no,  114 
Cardio-accelerator  center,  295 
-inhibitory  center,  289 

postganglionic  neurons,  295 
Carotid  canal,  196 
plexus,  316,  317 

Cartilage  of  the  nasal  septum,  39,  40,  81,  82 
Cartilages  of  the  external  nose,  39,  40,  66 
Cartilagines  alares  minores,  70 
sesamoideae  nasi,  70 
vomeronasales,  82 
Cartilaginous  nasal  capsule,  38,  43,  88,  175 

septum,  81 

Cartilage  alaris  major,  68,  82 
nasi  lateralis,  69,  70 
septi  nasi,  64,  81,  82 

Cavernous  sinus,  181.  182,  189,  193,  194,  195,  196 
relation   of,   to  sphenoidal  sinus,  etc.,  193, 

194,  195,  196 
thrombosis  of,  201 
tissue,  265,  292,  293,  297 
Cavum  nasi,  71 

septi  pellucidi,  335 
Cellulae  conchales,  211,  213,  221 
ethmoidales,  37,  87,  139,  205 
anterior,  207,  215,  219 
bullar,  208,  218 
frontal,  207,  216 
infundibular,  213,  216 
posterior,  207,  219 
Cephalometric  nasal  index,  62 
Cervical  ganglionated  cord,  289 
Choana?  (posterior  nares),  9,  10,  14,  15,  17,  74 


Chorda  tympani  nerve,  288 

Clivus  blumenbachii,  195,  196 

Commissural  tracts  of  olfactory  apparatus,  343 

344 
Comparative  anatomy  of  the  olfactory  organ,  35 1 

of  the  paranasal  sinuses,  350,  351 
Compressor  narium,  70 
Concha  nasalis  inferior,  19,  20,  21,  22,  32,  39,  42, 

87,  88 

media,  26,  34,  90,  91, 172 
superior,  95 
suprema  I,  96 
Concha;  nasales  suprema;  II  et  III,  97 

sphenoidales,  43,  175 
Conchal  cells  (see  celluhe  conchales),  141,  221, 

•222,  223,  224,  225,  226 

empyema  of,  226 
frequency  of,  226 
ostia  of,  226 

Congenital  defects  of  the  nose,  51 
fistula  of  the  lacrimal  sac,  243 
occlusion  of  choanae,  57 

of  nares,  57 

Coronary  artery  (A.  labialis  superior),  278 
Corpora  mammillaria,  337,  338 
Corticobulbar  fibers,  292 
Corticopontine  fibers,  292 
Corticospinal  fibers,  292 
Cribriform  plate  of  the  ethmoid,  47,  95 
Crista  conchalis,  88,  89 
lacrimalis, 
anterior,  244 
posterior,  244 
lateralis,  84 
nasalis,  64.  81 
suprema,  35,  91 


Dacryocystitis,  233 
Dacryocystorhinostomy,  237 
Dacryocystotomy,  253 
Deficiencies  of  the  osseous  walls 

of  ethmoidal  cells,  212 

of  frontal  sinus,  169 

of  maxillary  sinus,  132 

of  sphenoidal  sinus,  201 
Definitive  hard  palate,  12,  13,  14 

nasal  fossae,  17,  1 8 

septum,  37,  38 

Deflections  of  the  nasal  septum,  83,  84,  85. 
Depressor  alae  nasi,  71 

septi  nasi,  71 
Dermoids,  57 

Descending  palatine  artery,  278 
Diagonal  band  of  Broca,  333 


INDEX 


361 


Diaphragma  sellae,  189 

Dilatores  naris,  70 

Diminutive  sphenoidal  sinuses,  197,  198 

Disease  of  the  nose, 

relation  to  bronchial  asthma,  296 
Diverticula  of  the  frontal  sinus,  154,  155,  156,  157 

of  the  lacrimal  sac,  243 

of  the  nasolacrimal  duct,  243,  250,  251,  252 

of  the  sphenoidal  sinus,  184 
Dorsal  longitudinal  bundle  (Schutz's),  342 
Ductus  nasofrontalis,  162,  163,  164,  166,  167,  168 

lacrimales,  237,  247 

nasolacrimalis,  90,  237,  248 
Duplication  of  the  frontal  sinus,  150—152 

of  the  maxillary  ostium,  129,  130 

of  the  maxillary  sinus,  118,  119,  121,  122 
Dura  mater,  184,  185,  189,  193,  214 


Ectoturbinals,  27,  28 

Efferent  neurons,  291 

Endonasal  dacryocystotomy,  253 

Endoturbinals,  18 

Erectile  tissue,  265,  292,  293,  297 

Ethmofrontal  cells,  211,  216,  219,  221 

Ethmoid  bone,  40 

articulations  of.  212 
cribriform  plate  of,  40 
development  of,  40,  41 
orbital  plate  of,  40 
perpendicular  plate  of,  80 
field, 

extensions  of,  infection  in,  233 
notch,  63 
Ethmoidal  arteries,  277 

bulk,  29,  31,  32,  92,  94,  127 
cells,  40,  94,  205,  206,  208,  242,  351 
adult  stage,  205,  211-233 

classification  of,  212,  Table  M,  213 
dehiscences  of,  212 

extensions  of,  207,  208,  209,  224,  225,  233 
practical  considerations  of,  226,  227,  228, 

229 

roentgenography,  230, 231, 232, 233 
anterior,  32,  34,  207,  209 
childhood  stage  of,  206,  207,  208,  209,  210, 

211 

operations  during,  229,  230 
size  of,  211,  Table/, 
skiagrams  of,  210 
drainage  of,  233 
fetal  stage  of,  205 
posterior,  35,  36,  207,  209,  219 
conchae  (see  conchae),  22,  23,  24,  25 
fissure,  96 


Ethmoidal  fold,  21,22 

infundibulum    (see   infundibitlum  ethmoid  ale), 
28,  30,  31,  35,91,  101,  103,  119,  128,  129, 
140,  141,  142,  143,  152 
labyrinth,  159,  207,  211,  220,  352 
boundaries  of,  211 
development  of,  40,  41 
extension  of,  211,  212 
mucous  membrane  of,  268,  270 
size  of,  Table  N,  214 
Ethmolacrimal  cells,  211 
Ethmomaxillary  cells,  211,  219,  220 

sinus,  220 

Ethmopalatine  cells.  211 
Ethmosphenoidal  cells,  211,  219,  220 
Ethmoturbinal  fold,  20,  222 
Ethmoturbinals  (see  conchae),  21 
Eustachian  tube,  72,  201,  202 
External  maxillary  artery,  275,  278 
nasal  rami,  312 
nose,  61,  62 
bones  of,  63 

congenital  absence  of,  56 
embryonic,  48 
lymphatics  of,   282 
muscles  of,  70 
Exteroceptive  arcs,  293 


Facial  artery  (see  External jnaxillary  artery),  275, 
278 

canal,  316 

nerve,  286,  287,  289 

nucleus,  315 

Fascia  dentata  hippocampi,  333 
Fasciculus  mammillotegmentalis,  342 

retroflexus  of  Meynert,  336,  342 
Fasciola  cinerea,  333 
Fimbria  hippocampi,  334 
First  supreme  nasal  concha  and  meatus,  96 
Fistulas,  congenital  dermoids,  57 
Foramen  lacerum  medium,  196 

ovale,  178 

rotundum,  178,  201,  318 

sphenopalatinum,  275 
Fornix,  335 
Fossa  canina  (see  canine  fossa),  no 

hypophyseos,  189 

nasalis,  71 

prenasalis,  66 

pterygopalatina  (sphenomaxillary),  179 

sacci  lacrimalis,  244 

Frontal  bone,  45,  63,  66,  141,  144,  146,  148,  150, 
158,  169 

bulla,  152,  153,  154,  218,  219 


362 


INDEX 


Frontal  bone  cells,  140,  216 
conchae  (see  frontal  folds),  34 
ethmoidal  cells,  216 
folds,  33,  35,  161 
furrows,  31,  33,  34,  140,  141,  142,  161,  162, 

163, 164, 165, 166, 207, 216 
lobe  of  brain, 

relation  to  frontal  sinus,  146 
process,  48 

recess,  35,  140,  141,  166,  168,  207,  242 
sinus  (see  Sinus  frontalis),  32,  34,  93,  95,  208, 

216,  218,  242 
adult  stage  of,  146-1 70 
agenesis  of,  146, 157, 158, 159,  160,  170 
childhood  stage  of ,  143, 144, 145, 146 

measurements  of,  145,  Table  F 
clinical  considerations  of,  168-172 
deficiencies  of  osseous  walls  of,  169 
diverticula  of ,  154-157 
extensive  pneumatizations  of,  147-150 
fetal  stage  of ,  130-143 
frontal  bulk  of,  152, 153 
mucous  membrane  of,  268,  270 
nasofrontal  connections  of,  160-166 

duct  of,  166,  167,  168 
'•purred  pain,  disease  of,  303 
relation  of,  frontal  lobe  of  brain,  146 

op  tic  nerve,  193 
septum  of,  169 
size  of,  147,  Tables  G,  H 
skiagrams  of,  170-172,  227,  228 
supernumerary    frontal    sinuses,     150-152, 

159, 169, 170 
topography  of ,  1 5 1 
variations  of ,  146, 147,  157,  169 
Fronto-lacrimo-maxillary  suture  line,     244 
Frontonasal  process,  4,  37,  38 


Ganglion, 

geniculate,  289,  305,  316 

habenulse,  336 

semilunar  (Gasseri),  285,  308,  316,  317 

sphenopalatine,  314 
Gasserian  ganglion,  285,  308,  316,  317 
Geniculate  ganglion,  289,  305,  316 
Genital  spots  of  Fleiss,  271,  272,  300,  301 
Giacomoni,  band  of,  334 
Globular  process,  4 
Glossopharyngeal  nerve,  286,  287 
Gnathnic  index,  74 
Great  deep  petrosal  nerve,  306,  316,  317 

palatine  artery,  278 

superficial  petrosal  nerve,  288.  289,  205,  303) 


Greater  alar  cartilage,  68,  69,  82 
Gyrus  dentatus,  333,  334 

epicallosus,  329,  333 

subcallosus,  333 

H 

Habenular  bodies  (see  Habenular  ganglion),  340 
ganglion,  336,  340 
triangle,  336 
Harelip,  51,  53,  54,  55 
Hiatus  of  the  maxillary  sinus,  in 

semilunaris,  93,  127,  128,  129,  166 
Hippocampal  commissure,  335 

digitations,  334 

Hippocampus  (hippocampus  major),  329,  334 
Huschke,  vomerine  cartilages  of,  270 
Hypophyseal  fossa,  189,  195 
Hypophysis  cerebri,  180,  182,  188,  189,  190 
relations  of, 

to  basilar  artery,  189 
to  cavernous  sinus,  1 89 
to  internal  carotid  artery,  189 
to  optic  commissure,  189 
to  pons,  189 
to  sphenoidal  sinus,  189 
tumors  of,  190 


Incisive  foramen,  55,  76 
Incisor  teeth,  53,  54,  55 
Inferior  bullar  fold,  32 

nasal  concha  (turbinate),  20,  88,  238,  255,  262, 
272 

nasal  meatus,  20,  89,  107,  202,  239,  245,  246, 

254 

Infrabullar  furrow,  31,  94 
Infranasal  area,  48 
Infraorbital  artery,  278 

canal,  45, 105,  108,  318 

nerve,  312 

Infratemporal  fossa,  no 
Infundibular  cells,  141,  142,  152,  208,    216,  242 

fold,  29,  30,  31,  33 

group  of  anterior  ethmoidal  cells,  216,  217 
Infundibulum  ethmoidale,  28,  30,  31,  35,  92,  93, 
119,  128,  129,  140,  141,  142,  143,  152,  155, 
162,  163,  164,  165,  166,  167,  168,  171,  172, 
207,  225,233,253 

of  the  frontal  sinus,  93,  166,  167,  168 

of  the  hypophysis  cerebri,  188 
Inhibitory  preganglionic  neurons,  295 
Intermaxillary  mass,  48 

process,  14,  16 
Intermediate  olfactory  stria,  339,  340 


INDEX 


363 


Internal  carotid  artery,  196,  275 

relations  to  abducens  nerve,  196 
cavernous  sinus,  196 
hypophyseal  fossa,  196 
sphenoidal  sinus,  196 
nasal  rami,  312 
nose,  71 
Internasal  bones,  66 

suture,  64,  66 

Interpeduncular  ganglion,  336 
Intranasal  dacryocystotomy,  237 


Jacobson's  organ   (see    Vomeronasal  organ),   g, 

18,  47,  48,  270,  271,  325,  327,  328 
cartilage  (see  Vomeronasal  cartilage),  68,  82 

L 

Lacrimal  bone,  42,  43,  238,  239,  444,  245 
canal,  248 
canaliculi,  237 
ducts,  237,  239,  242 
orifices  of,  249 
sacculations  of,  247 
variations  of,  242,  243 
fossa,  244,  245,  247 
papilla,  242,  247 
process,  88 
puncta,  242,  247 
sac,  237,  239,  240,  242,  243,  247,  248,  249,  250, 

252,  253 

congenital  fistula  of,  243 
diverticula  of,  243 
embryology  of,  49,  50 
Lacrimonasal  membrane,  244 
Lamina  cribrosa,  40 
papyracea,  40,  233 
perpendicularis,  64,  80 
rostralis,  333 
terminalis,  243 

Lateral  ethmoid  mass,  219,  222 
nasal  cartilage,  39,  40,  64,  69 
processes,  4,  n,  237 
waU,  18,  86,  87 
olfactory  stria,  339 

Levator  labii  superioris  alaeque  nasi,  70 
Limen  nasi,  73,  262 

vestibuli,  73 
Lingual  nerve,  288 
Longitudinal  stria,  333 
Lymphatics  of  external  nose,  282 
of  the  nasal  cavity,  280,  281 
of  the  nose  and  paranasal  sinuses,  279,  280, 

281,  282 
Lyre  (transverse  fornix),  343 


M 


Major  nasal  conchae,  18 

meatuses,  18 

Mammillary  bodies,  337,  338,  340 
Mammillotegmental  bundle  of  Gudden,  342 
Mandibular  nerve,  196 
Maxilla,  44,  238 

frontal  processes  of,  65,  66 

ossification  of,  44 
Maxillary  fold,  22 

nerve,  197,  201,  285,  306,  307 
relation  to  maxillary  sinus,  306 

ostium,  103,  127,  128,  129 

pouches,  103 

processes,  4,  5,  n,  51,  55,  88,  237 
fusion  of,  48 

sinus,  76,  101, 164, 166, 179,  220,  233,  241,  242, 

247,  353 
adult  stage  of,  109-134 

boundaries  of,  109,  no,  in 
communication  with    the   superior   nasal 

meatus,  102,  118,  119,  120 
decrease  in  size  of,  122,  123 
duplication  of ,  101, 118, 119, 120, 121, 122 
enlargement  of,  122 
location  of,  109 
relation  of  the  sinus  floor  to  the  naral  floor, 

in 

canine  fossa,  114 
teeth,  112 

to  the  vi'eiior  nu.,al  meatus,  in,  114 
ridges,  crescentic  projections  and  septa 

on  walls  of,  116,  117,  118 
size  of,  see  tables  C,  D,  and  E,  122,  123, 

124,  125,  126,  127 
variations  of,  126 

childhood  stage  of,  104, 105, 106, 107, 108, 109 
dimensions  of  (Table  B),  104,  105,  106, 

107,  108 

endonasal  procedures  during,  107 
relations  to  dentition,  106 

infraorbital  canal,  106,  108 
size  of  (Table  B),  108 
skiagraphy  of,  108,  109 
communication    with    the    inferior    nasal 

meatus,  102 
fetal  stage  of,  36,  101,  103,  104 

size  of  (Table  A),  104 
infraorbital  recess  of,  253 
mucous  membrane  of,  268,  270 
openings  of,  oatia,  129 
practical  considerations  of,  133,  134,  135 
radiography  of,  133,  134,  135 
Maxilloturbinal,  19,  42,  87,  88 
Meatus  nasi,  71 


364 


INDEX 


Meatus  nasi,  inferior,  87,  89 

medius,  28,  33,  87,  91,  92,  95,  96,  127 
superior,  95,  96 
supremus,  87,  96 

Meckel's  nasal  ganglion,  221,  288,  314 
Medial  lemniscus,  286 
longitudinal  fasciculus,  286 
olfactory  stria,  339 

Median  subcallosal  sulcus  of  Retzius,  333 
Medulla,  285,  286 

Medullary  stria  of  the  thalamus,  336,  337 
Membranous  conchal  folds,  19 
lacrimal  ducts,  247 
passageways, 

nasal  and  paranasal  relations  of,  252,  253 
sac,  239,  248 
nasal  capsule,  38 
nasolacrimal  duct,  239 
portion  of  the  nasal  septum,  82,  83 
Metopic  suture,  45,  145 

fontanelle,  45 
Middle  conchal  sinus,  226 
nasal  concha,  90,  171,  271 

meatus,  20,  25,  91,  92,  107,  141,  162,  163, 

166,  168,  171,  172,  243 
palatine  nerve,  310 

superior  alveolar  rajnus  (dental  nerve),  311 
Minor   conchae,    descending   ramus    of    middle 

meatus,  30 
nasal  conchae,  27,  28 
Mitral  cells,  339 
Molar,  third, 

impaction  of,  116 
Motor  nuclei  of,  116 
facial,  286 
trigeminal,  286 
Mucosal  diverticula, 

of  the  sphenoid  sinus,  184,  185,  186 
relations  to  the  dura,  185,  186,  187 
Mucous  membrane  of, 

ethmoidal  labyrinth,  268,  270 
frontal  sinus,  268,  270 
maxillary  sinus,  268,  270 
nasal  fossae,  261 
sphenoidal  sinus,  268,  270 
Muscles  of  the  external  nose,  70 
compressor  narium,  70 
depressor  alae  nasi,  71 

septi  nasi,  71 
dilatores  nans,  71 

levator  labii  superioris  alaeque  nasi,  70 
quadratus  labii  superioris,  70 


N 


Nares,  10,  62,  72 
anterior,  10,  14,  62 


Nares,  congenital  occlusion  of,  57 

posterior,  14,  15 
Nasal  atrium,  88,  97 
bones,  42,  65,  66 
bridge,  63,  66 
capsule,  38,  176 
cartilages, 

greater  alar,  68,  70,  82 

lateral,  69 

lesser  alar,  70 

septal,  81,  82 

sesamoid,  70 

vomeronasal,  68,  82 

cavity,  71,  76 

lymphatics,  280 
concha;,  18,  19,  27,  28,  71 
disorders, 

relation  to  asthma,  296 

to  dysmenorrhea,  297,  301,  302 
to  menses,  297 
to  priapism,  298 
distribution,    maxillary    division     trigeminal 

nerve,  306 
fossae,  1 6,  45,  66,  71 

apertures  of,  66 

dimensions  of,  72 

floor  of,  72 

lateral  wall  of,  72,  86,  87 

medial  wall  of,  77 

mucous  membrane  of, 

pars  respiratoria,  261,  262,  263,  264,  265, 

266 
olfactoria,  261,  267,  268 

primitive,  37 

relation  to  the  brain,  344 

roof  of,  77 

furrows,  accessory,  27-35 
glands,  47 
index,  62 
meatuses,  71 

accessory,  27,  28 

development  of,  19,  27 

inferior,  20,  89 

middle,  20,  91 

superior,  21,  95 

ist  supreme,  21,  96 

ad  supreme,  21 

3d  supreme,  21 
mucous  membrane,  261 

erectile  portion  of,  272 
muscles,  70,  71 
neuroses,  294 

ostium  of  the  frontal  sinus,  172 
processes,  4 

lateral,  4,  37,  48 

maxillary,  4,  53,  55 


INDEX 


365 


Nasal  processes,  media!,  4,  37,  55 

and  paranasal  relations  of  the  membranous 

lacrimal  passageways,  252,  253 
olfactory  mucous  membrane,  261,  267,  268 
pyramid,  63 

referred  pains,  302,  303,  304,  305,  306 
respiratory  mucous  membrane,  263,  264,  265 

cavernous  tissue  of,  265,  292,  293-297 

ciliated  cells  of,  262,  263 
septum,  38 

buccal  border  of,  55 

cartilaginous,  81 

definitive,  37 

deviations  of,  83 

mobile,  83 

mucous  membrane  of,  38,  261 

osseous,  78 

primitive,  16 

secondary,  16,  37 
skeleton,  38 

spine  of  the  frontal  bone,  81 
turbinates  (see  Concha) 
vestibule,  261 
Nasociliary  nerve,  277 
Nasoencephalic  relations,  344 
Xasofacial  angles,  63 

Nasofrontal  connections,  160,  161,  162,  163 
duct,  93,  142,  143,  153,  162,  163,  164,  165,  166, 

167,  168,  216 
Nasolabial  sulcus,  63 
Nasolacrimal  canal,  241,  244,  245 

ostium  of,  245 
duct,  239,  240,  241,  242,  244,  248,  249,  250 

communication     with     the     middle     nasal 
meatus,  243 

diver ticula  of,  250,  251,  252 

embryology  of,  50,  51 

isthmus  of,  249 

membranous,  239,  249 

nasal  end  of,  255 

relation  to  the  maxillary  sinus,  253 

uncanalization  of,  243,  244 

valves  of,  250,  251,  252 
ostium,  89,  90,  241,  249,  251,  253 

location  of,  253,  254 

number  of,  254 

types  of,  251,  254,  255 
passageways,  237 

canalization  of,  239 

clinical  remarks,  255,  256,  257,  258 

development,  49,  237,  238,  239,  240,  241,  242 

lymphatics  of,  255 

relations  of, 

to  conjunct! val  culdesac,  238 

to  nasal  meatuses,  238 

to  paranasal  sinuses,  240,  241,  242,  253 


Nasolacrimal  passageways,  variations  and  ano- 
malies, 242,  243,  244 
venous  plexuses  of,  255 
sac,  49,  50,  237,  248 
Naso-optic  fissure,  48,  50,  237,  243 
Nasopalatine  artery,  276,  278 

canal,  76,  121,  122 
Nasosexual  relations,   296,   297,   298,   299,  300, 

301,  302 

Nasoturbinal  (agger  nasi),  18,  26,  87,  97 
Nasus  externus,  71 

internus,  61,  71 

Nerve  or  nerves  (nervus  or  nervi), 
abducens,  194 
canalis  pterygoidei  Vidii,  177,   179,   183,   201, 

315,  320,  321 
ethmoidalis  anterior,  313 
glossopalatinus,  314 
intermedius,  288,  289,  305,  314 
maxillaris,  177,  197,  285,  303,  306,  307 
nasociliary,  277,  313 
olfactorius,  47,  325,  326,  338 
ophthalmicus,  177,  179,  185,  285,  303 
palatini,  310,  311 
petrosus  pro  fund  us  major,  316 

super ficialis  major,  316 
sphenopalatini,  275,  307,  308,  309 
terminalis,  325,  326,  327 
trigeminal,  177,  285,  286,  287,  306-318 
vomeronasalis,  327 
Neuron  arcs,  291 
Nose,  49,  61,  63 

congenital  defects  of,  51 
development,  3,  4,  13,  14 
erectile  tissue  of,  265,  292,  296,  297 
nomenclature,  27,  28 
and  paranasal  sinuses, 
arterial  supply  of,  275 
lymphatic  supply  of,  279 
sensory  nerves  of,  285 
sympathetic  nerves  of,  285 
physiology  of,  347,  348,  349,  35° 
Schaeffer's  types  of,  62 
sympathetic  fibers  of,  302,  303,  304,  305,  306 
Topinard's  types  of,  62 
Nucleus, 
ala  cinerea,  316 
ambiguus,  286,  295 
amygdalae,  338 
oculomotor,  286 
trigeminus,  285,  286,  287 
relation  to  nuclei  of,  286 
abducent,  286 
centers  of,  286 
oculomotor,  286 
secretomotor,  286 


366 


INDEX 


Nucleus,  trigeminus,  relation  to  trochlear,  286 
vasoconstrictor,  286 
vasoinhibitor,  286 
sensory  nucleus  of,  285,  286 


Oculomotor  nerve,  179 
Odors, 

classification  of,  356 
Olfactory  apparatus,  325 
bulb,  328,  329,  330,  354,  356 
bundle  of  Wallenburg,  342 
cells,  271,  325,  326,  327 
central  organ  of,  328-341 

anterior  perforated  substance,  331 

fascia  dentata  hippocampi,  333,  334 

fornix,  335 

habenular  triangle,  336 

hippocampus,  334,  349 

longitudinal  striae,  333 

mammillary  bodies,  338 

medullary  stria  of  the  thalamus,  336.  337 

olfactory  brain,  328 
bulb,  330 
lobe,  329 
tract,  330,  331 
trigone,  331 

parolfactory  area  of  Broca,  331,  332 

septum  pellucidum,  335,  336 

stria  terminalis,  338 

subcallosal  gyrus,  333 

supracallosal  gyrus,  333 

uncus,  334,  335 
cortical  centers,  341 
fissure,  107 
fossae,  38 
glands,  268 
glomeruli,  326,  338 
hairs,  267 
lobes,  354 
nasal  mucosa, 

phylogeny  of,  351 
nerves,  47,  325,  326,  338 
neurons,  338,  339,  340 
pathways,  afferent  fibers  of,  341,  342,  343,  344 

commissural  fibers  of,  343,  344 

efferent  fibers  of,  343 
peripheral  organ  of,  325-328 

olfactory  nerve,  325,  326 

terminal  nerve,  325,  326,  327 

vomeronasal  nerve,  325,  326,  327 
pit,  47,  48,  357 
portion  of  the  nasal  mucous  membrane,  266, 

267,  268 
receptors,  355 
reflex  and  cortical  connections,338, 339, 340, 341 


Olfactory  apparatus,  sensation,  354,  355,  356 

357,  358 

relation  to  sexual  organs,  357 
to  sexual  reflexes,  296,  297 
sensation,  350,  351,  352,  354 
striae,  331 
sulcus,  88,  97,  98 
tract,  329,  330,  331 
trigone,  331 
Ophthalmic  artery,  275,  277 

nerve,  179,  180,  181,  182,  183,  184,  185 
vein,  201 
Optic  chiasm,  191 

commissure,  180,  189,  191 
relations  of, 

to  the  paranasal  sinuses,  190, 191, 192, 193 
to  the  posterior  ethmoidal  cells,  191,  192, 

193 

to  the  sphenoidal  sinus,  191,  192 
Optic  nerve,  177,  179-185,  285,  303 
relations  of, 

to  frontal  sinus,  193 
to  maxillary  sinus,  193 
to  ostium  sphenoidale,  192 
to  sphenoidal  sinus,  191,  192,  193 
neuritis,  190,  191,  200 
tracts,  189 
Orbital  rami,  309 
Organon  vomeronasale  Jacobsonii,  9,  18,  47,  48, 

270,  271,  325,  328 
Os  frontale,  45 
lacrimale,  42 
nasale,  63 
palatinum,  42 
sphenoidale,  40,  43 
Osseous  framework  of  the  lateral  nasal  wall,  87, 

88 

nasolacrimal  canal,  245,  246,  247,  253 
relation  to, 

anterior  ethmoidal  cells,  247 
maxillary  sinus,  247 
Ossiculum  Bertini,  43,  175 
Ostium  of  the  frontal  sinus,  166,  167,  168 
maxillare,  93,  94,  127,  128,  129,  164,  166,  172 
dimensions  of,  103 
duplication  of,  no,  129,  130 
location  of,  127,  129,  134 
relation  to  infundibulum  ethmoidale,  1 1 1 
accessorium,  92,  103,  in,  130,  131,  132,  133 
genesis  of,  131,  132 
location  of,  130 
nasolacrimale,  51,  89,  90,  253 

types  of,  90,  249 
sphenoidale,  98,  175,  180,  181,  184,  192 

deviations  from  the  usual  location,  measure- 
ments, Table  /,  188 


INDEX 


367 


Ostium  sphenoidale,  location  of,  187 
primitive,  176 
size  of,  177 


Palatal  processes,  12-15 

sinus,  178 
Palate, 

bipartite,  55 

definitive,  12,  13 

hard  (palatum  durum),  55 

ossification  of,  42 

primitive,  n 

secondary,  15 

soft  (palatum  molle),  13,  55 

tripartite,  55 
Palatine  nerves,  310 
Papillae  palatina,  76 

Paranasal  sinuses   (see  frontal,  maxillary,  sphe- 
noidal,  ethmoidal) 

blood  vessels  of,  275-279 

cilia  of,  270 

comparative  anatomy  of,  350-352 

functions  of,  35°-353 

lymphatics  of,  281,  282 

mucous  membrane  of,  268-270 

phytogeny  of,  350-352 

referred  pains  of,  302,  304,  305 

relations  of,  to  brain,  344 

rudiments  of,  36,  37,  71 
Parolfactory  area,  Broca,  329,  331,  339 
Pars  olfactoria,  nasal  mucous  membrane,  266- 
268 

intermedia,  288,  289,  305 

respiratoria,  nasal  mucous  membrane,  262-266 
Partes  laterales  nasi,  63 
Partial  osseous  septa, 

frontal  sinus,  169 

maxillary  sinus,  116 

sphenoidal  sinus,  183 
Peduncle  of  corpus  callosum,  333 
Perforation,  nasal  septum,  86 
Perpendicular  plate,  palate  bone,  179 
Pes  hippocampi,  334 
Pharyngeal  artery,  275,  278 

canal,  1 80,  318 

Physiological  addenda,  347-358 
Physiology  of  the  nose,  347-350 
Pituitary  body  (see  hypophysis  cerebri),  188,  189 
Plexus  cavernosi  concharum,  89,  265 
Plica  lacrimalis,  254 
Plicae  septi,  37,  38,  78 
Pneumatization, 

of  frontal  bone,  147-150 

of  maxilla,  122,  123 


Pneumatization,  of  sphenoid  bone,  178,  179,  180 
Posterior  ethmoidal  arteries,  278 

cells,  179,  180,  198,  207,  208,  219 
communications  of,  219 
extensions  of,  212,  219,  221 
genesis  of,  219 
relations  of, 

to  optic  nerve,  191-193,  220,  221 
to  sphenopalatine  ganglion,  221 
foramen,  278 
nerve,  313 

longitudinal  bundle,  336 
nares  (see  Ckoana),  38,  46,  71,  73,  355 
nasal  septal  arteries,  276 
palatine  nerves,  310 
superior  alveolar  rami,  310,  311 
dental  nerves,  310,  311 
nasal  rami,  310 

Postganglionic  neurons,  287,  288,  289 
Pre-ethmoidal  recess,  216 
Preganglionic  neurons,  287-289,  295,  296 
Premaxillae,  53 
Premaxillary  process,  37 
Primary  choanae  (posterior  nares),  9 
nasal  fossae,  7,  47 
septum,  15,  37 

Primitive  sphenoidal  ostium,  176 
Processus  alveolaris,  no,  in,  112 
ethmoidalis,  88 
lacrimalis,  89 
paranasalis,  39,  44 
sphenoidalis  septi  cartilaginei,  82 
uncinatus,  28,  29,  33,  34,  93,  94,  127,  128,  129, 

140,   165,  172,   222 

Projecting  nose,  56 

Pterygoid  canal,  177,  320,  321 

Pterygopalatine  fossa  (see  also  Sphenomaxillary 

fossa),  no,  179,  318 
canal,  180,  318 
Pyriform  aperture,  66,  246 


Quadratus  labii  superioris,  70 


Radix  nasi,  63 

Rami  nasales  laterales,  313 

mediates,  313 

orbitales,  309 

posteriores  superiores,  310 

inferiores,  108 

Ramus  nasalis  externus,  314 
Recessus  alveolaris,  108 

aoicis,  73 


INDEX 


Recessus,  frontalis,  33,  139,  140,  141,  143,  144, 
152,  155,  157,  158,  161,  162,  163,  164,  172 
palatinus,  120 
sphenoethmoidalis,  95,  97 
Referred  nasal  manifestations,  294,  295,  296 
Reflex  circuits,  291,  292,  293 
antagonistic,  292 
inhibiting,  292 
nasal  manifestations,  293 
nasal  pains,  so-called,  302,  303,  304,  305,  306 
olfactory  pathways,  341 

centers,  340 

sympathetic  neurons,  291,  292 
Regio  vestibularis,  261 
olfactoria,  261,  266,  267,  268 
respiratoria,  261,  262,  263,  264,  265,  266 
Relation,  brain  to  \v  alls  of  nasal  fossa?  and  para- 
nasal  sinuses,  344 
Respiratory  portion,  nasal  mucous  membrane, 

262,  263,  264,  265,  266,  307 
Ridges  on  wall,  maxillary  sinus,  117,  118 


Saccus  lacrimalis,  49,  50,  237,  240-253 

Second  and  third  supreme  nasal  conchae  and  the 

related  meatuses,  97,  98 
Secondary  nasal  fossae,  17,  1 8 

septum,  1 6,  38 
olfactory  centre,  340,  341 
Sella  turcica,  189 
Semilunar  ganglion,  285,  308,  316,  317 

hiatus,  93,  127,  162,  171,  216 
Sensory  nerves  of  the  nose  and  paranasal  sinuses, 

285 
Septa  on  the  walls  of  the  maxillary  sinus,  116, 

117,  118 
Septal  cartilage,  38,  64,  81,  82 

folds  (see  Plica),  38,  78 
Septum  lucidum,  335 
mobile  nasi,  83 
nasi  cartilagineum,  81 
membranaceum,  83 
osseum,  78 
plicae,  38,  78 

sinuum  frontalium,  145,  146,  169 
sinuum  sphenoidalium,  187 
Sesamoid  nasal  cartilages,  68,  70 
Sinus  frontalis  (see  Frontal  sinus),  139 

adult  stage  of,  146,  147,  148,  149,  150,  151, 
152, 153, 154,  155,  156,  iS7, 158, 159.  160, 
161,  162,  163,  164,  165,  166,  167,  168, 
169,  170 

childhood  stage  of,  143,  144,  145,  146 
fetal  stage  of,  139,  140,  141,  142,  143 
maxillaris  (see  Maxillary  simis),  101 


Sinus  maxillaris,  adult  stage  of,  109-135 

childhood  stage  of,  104,  105,  106,  107,  i< 

109 

fetal  stage  of,  36,  101,  103,  104 
pseudo  paranasal,  226 
sphenoidalis  (see  Sphenoidal  sinus),  1715 
adult  stage  of,  178-202 
childhood  stage  of,  176,  177,  178 
fetal  stage  of,  175,  176 
superior  sagittal,  279 
terminalis,  175,  176 

Skeleton  changes  incident  to  growth,  45 
Solid  nasolacrimal  duct,  239 
Somatic  sensory  fibers  of, 

glossopharyngeal,  286 
pars  intermedia,  286 
vagus,  286 
Sphenoethmoidal  cells,  220,  221 

recess,  96,  97,  180,  187 
Sphenoid  bone,  43 
Sphenoidal  conchas,  43,  175 
fissure,  195 
sinus,  175 

adult  stage  of,  178 
agenesis  of,  198 
anlage  of,  36 
caudal  wall  of.  182,  183 
relation, 

to  posterior  nares,  182 
to  Vidian  nerve,  183,  320,  321 
cephalic  wall  of, 
relation, 

to  hypophysis  cerebri,  182,  189 
to  optic  commissure,  182,  189 
childhood  stage  of,  176,  177,  178 
growth  of,  Table  /,  178 
relation, 

to  trigeminal  nerve,  177 
To  Vidian  nerve,  177 
curetting  of,  201 
'     disease  of,  199,  200,  201 
diverticula  of,  184,  185,  186 
mucosal, 
relation  of, 

to  dura,  185,  186,  187 
dorsal  wall  of,  182 
relation  of, 

to  basilar  artery,  182 
to  pons,  182 
fetal  stage  of,  175,  176 

size  of,  1 76 

lateral  wall  of,  181,  182 
location  of,  178 
medial  wall  of,  183 
nerves  of,  309 
ostium  of,  43,  187 


INDEX 


369 


Sphenoidal  sinus,  partial  osseous  septa  of,  18.3, 

184 

pneumatization  of,  178,  179,  184,  189 
primary  ostium  of,  187 
recesses  of,  178 
relations  of, 

to  basilar  artery,  182 
to  cavernous  sinus,  181,  182,  193-196 
to  ethmoidal  conchae,  181 
to  foramen  ovale,  178 
to  foramen  rotundum,  178 
to  Gasserian  ganglion,  196,  197 
to  hypophysis  cerebri,  182,  188,  189 
to  mandibular  nerve,  196 
to  maxillary  sinus,  179 
to  optic  nerve,  179,  197 
to  sphenopalatine  ganglion,  180 
to  Vidian  nerve,  177,  320,  321 
septum  of,  187 
size  of,  Table  K,  188 
topography  of,  180,  181 
ventral  wall  of,  181 
X-rays  of,  199,  200,  201 

in  infants,  199,  200 
Sphenomaxillary  fissure,  309 

fossa  (see  Pier ygopalatine  fossa),  no,  179,  318 
ganglion,  314 

Sphenopalatine  artery,  275,  276 
foramen,  179,  180,  275,  318 
ganglion  (Meckel's  ganglion),  180,  221,  288, 

289,  303,  305,  306,  307,  308,  310,  314 
anatomic  relations  of,  318,  319,  320 
disease  of,  304 
fibers  of,  307,  308,  309 
location  of,  314,  318 
motor  root  of,  314 
sensory  root  of,  317,  318 
somatic  sensory  neurons  of,  315 
sympathetic  afferent  neurons  of,  316 

root  of,  316,  317 
nerve,  275,  307,  308,  309 
Sphenoturbinals  (see  Sphenoidal  conchie),  41,  43, 

i7S 

Stratum  griseum,  333 
Striae  longitudinales,  333 

medullaris  thalami,  336,  339,  342 
terminalis,  338 
Subcallosal  gyrus,  329,  333 
Substantia  gelatinosa  of  Rolando,  285 

perforata  anterior,  329,  331 
Sulcus  ethmoidalis,  64 
nasalis  posterior,  72 
olfactorius,  88,  97,  98 
Superciliary  ridges,  146,  169 
Superior  bullar  fold,  32 

cervical  sympathetic  ganglion,  287,  289,  317 
24 


Superior  dental  plexus,  311,  312 

dural  sinus,  279 

labial  artery,  276 

nasal  concha,  32,  95 

meatus,  95,  96,  220,  224,  275 

orbital  fissure,  179,  195,  313 
Supernumerary  frontal   sinuses,    150,    151,    152, 

169,  170 
Suprabullar  furrow,  30,  92,  141 

recess,  30,  32,  95 
Supracallosal  gyrus,  333 
Sustentacular  cells  (see  Nasal  mucous  membrane}, 

266,  267 
Sympathetic  afferent  neurons,  289 

efferent  neurons.  289,  298 
postganglionic,  288 
preganglionic,  288 

fibers,  287,  288 

nerves  of  the  nose  and  paranasal  sinuses,  285, 
287 

sacral  efferent  fibers,  298 

system,  bulbar,  295 


Taenia  fimbriae,  334 

semicircularis  (stria  terminalis},  338 

thalami,  336 

Tegmental  bundle  of  Gudden,  342 
Terminal  nerve,  271,  325,  326,  327 

sinus  (nasal),  43,  44,  175 

stria,  338 

Thoracolumbar  sympathetic,  287,  295 
Topinard's  nasal  types,  62 
Tract  of  Vicq  d'Azyr,  343 
Tractus  habenulopeduncularis,  342 

mammillopeduncularis,  342 

mammillothalamicus  (Vicq  d'Azyr),  343 

olfactohabenularis,  342 

olfactomesencephalicus,  342 

olfactorius,  329,  330,  331 

olfactotegmentalis,  342 

tegmentalis,  342 
Transference  and  reference,   afferent  impulses, 

3°2,  3°3»  3°S.  3°6 
Transillumination,  228,  230 
Triangular  area  of  His,  48 
Trigeminal  nerve,  271,  313 

central  connections  of,  285,  286,  287 

divisions  of,  285 

nasal  distribution  of,  306-318 

terminal  nucleus  of,  285,  286 
Trigeminothalamic  tract,  286,  287,  294 
Trigonum  habenulse,  336 

olfactorium,  331 
Trochlear  nerve,  179 
Tuba  auditiva  Eustachii,  72,  201,  202 


370  INDEX 


Tuberculum  septi,  78,  271 
Turbinate  crest  (crista  conchalis),  88 
Turbinated  bones  (see  Concha  nasales) 

U 

Uncinate  process  (see  Procr.ssus  uncinalus),  34, 

92,  93,  an 
Uncus,  334,  335,  338,  356 


Vagus  nerve,  286,  287 

Valve  of  Hasner,  90,  254 

Valves  of  nasolacrimal  duct,  250,  251,  252 

Vasoconstrictor  center,  289,  290 

fibers,  288,  289 

Vasodilator  center,  288,  289,  290,  293,  299,  357 
Veins, 

anterior  facial,  279 

ethmoidal,  279 


Veins,  sphenopalatine,  279 

Venous  supply,  nose  and  paranasal  sinuses,  279 

Ventral  psalterium,  343 

wall,  sphenoidal  sinus,  181 
Ventricle  of  the  fornix  (Verga),  335 
Ventriculus  bulbi  olfactorii,  330 
Verga's  ventricle,  335 
Vestibulum  nasi,  73 
Vicq  d'Azyr,  tract  of,  343 
Vidian  canal,  177,  179,  180,  318 

dehiscences  of,  305,  306,  315,  316 

relation  to  sphenoidal  sinus,  320,  321 
Vidian  nerve,  177,  179,  183,  201,  320,  321 

relation  to  sphenoidal  sinus,  320,  321 
Vomer,  41,  42,  79 
Vomerine  cartilage  (Huschke),  270 
Vomero nasal  cartilage  (Jacobson),  68,  82,   270 

organ  (Jacobson),  9,  18,  47,  48,  325,  327,  328 
mucous  membrane  of,  270,  371 
nerve,  327 


. 


Ux. 


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